Exabyte Computer Drive EXB 8505 8mm User Manual

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510504-002  
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Changes and Enhancements to This Manual  
This revision (510504-002) of the EXB-8205 and EXB-8505 Product  
Specification for Standard and eXtended Length (XL) Configurations  
replaces the EXB-8205 8mm Cartridge Tape Subsystem Product  
Specification (510703) and the EXB-8505 8mm Cartridge Tape Subsystem  
Product Specification (510504). This manual includes the following  
changes and enhancements:  
The manual has been reorganized for easier reference. Chapters 1  
through 3 include a general description of the tape drives, tape drive  
functions, and related products; chapter 4 includes requirements for  
installation, operation, and maintenance; chapter 5 includes SCSI  
specifications; and chapters 6 and 7 include functional specifications and  
compliance with safety and regulatory standards.  
Information about the EXABYTE EXB-8205 and EXB-8505 has been  
consolidated into one manual. Information about the “eXtended Length”  
(XL) configurations of these tape drives has also been included.  
In the Related Products section, a description of the EXB-210 8mm  
Library has been included. Information about extended length media,  
including the Recognition System stripe on 160m XL EXATAPEä data  
cartridges has been added. Exabyte cleaning cartridge information has  
also been updated.  
Detailed information about the relationship between physical track  
structures and logical data formats has been added to the Physical  
Format section.  
May 1994  
EXB-8205 and EXB-8505  
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Product Warranty Caution  
The EXB-8205, EXB-8205XL, EXB-8505, and EXB-8505XL 8mm  
Cartridge Tape Subsystems are warranted to be free from defects in  
materials, parts, and workmanship and will conform to the current  
product specification upon delivery. For the specific details of your  
warranty, refer to your sales contract or contact the company from  
which the tape drive was purchased.  
The warranty for the EXB-8205, EXB-8205XL, EXB-8505, and  
EXB-8505XL shall not apply to failures caused by:  
Physical abuse or use not consistent with the operating instructions or  
product specifications provided by Exabytes personnel or agent for the  
applicable equipment.  
Use of any type of cleaning material other than an EXABYTE 8mm  
Cleaning Cartridge (or an Exabyte-approved cleaning cartridge).  
Modifications by other than Exabytes personnel or agent in any way  
other than those approved by Exabyte, provided the warranty shall not  
be voided by the repair or replacement of parts or the attachment of  
items in the manner described in maintenance or installation instructions  
provided by Exabyte.  
Repair by other than Exabytes personnel or agent in a manner contrary  
to the maintenance instructions provided by Exabyte.  
Removal of the Exabyte serial number tag.  
Physical abuse due to improper packaging of returns.  
CAUTION  
Returning the EXB-8205, EXB-8205XL, EXB-8505, or EXB-8505XL in  
unauthorized packaging may damage the unit and void the warranty.  
If you are returning the tape drive for repair, package it in its original  
packaging (or in replacement packaging obtained from your vendor).  
Refer to the packing instructions in this manual.  
If problems with the tape drive occur, contact your maintenance  
organization; do not void the product warranty by allowing  
untrained or unauthorized personnel to attempt repairs.  
EXB-8205 and EXB-8505  
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Contents  
1
Features  
1-1  
2
Recording Format  
2-1  
Track and Block Counts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19  
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3
4
Functional Description  
3-1  
Requirements for Use  
4-1  
5
Interface Specifications  
5-1  
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6
Functional Specifications  
6-1  
7
Safety and Regulatory Agency Compliance  
7-1  
Glossary  
Index  
G-1  
I-1  
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Figures  
Features  
Recording Format  
Figure 2-4 Position of the tape drives heads relative to the tracks  
Figure 2-7 Position of the tape drives heads relative to the tracks  
Figure 2-8 Physical block format for all logical formats  
Functional Description  
Requirements for Use  
EXB-8205 and EXB-8505  
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Tables  
Features  
Recording Format  
Table 2-3 Track and physical block counts for 8200 and 8200c formats . . . . . . . 2-20  
Table 2-4 Track and physical block counts for 8500 and 8500c formats . . . . . . . 2-20  
Requirements for Use  
Interface Specifications  
Functional Specifications  
EXB-8205 and EXB-8505  
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About This Manual  
This product specification describes the functional, performance, and  
environmental specifications for the following EXABYTE® 8mm  
Cartridge Tape Subsystems (tape drives):  
EXB-8205  
EXB-8205XL (extended length)  
EXB-8505  
EXB-8505XL (extended length)  
Intended Audience  
This manual is for engineering, purchasing, or marketing personnel  
who want to evaluate the EXB-8205, EXB-8205XL, EXB-8505, and  
EXB-8505XL to determine the feasibility of integrating them into  
product lines.  
How This Manual is Organized  
This manual contains the following chapters:  
Chapter 1 describes the features of the tape drives, including  
compatibility with other Exabyte 8mm Cartridge Tape  
Subsystems, data compression, tape capacity, and custom  
EEPROM options. This chapter also describes the physical  
features of the tape drives, including mechanical and electrical  
components.  
Chapter 2 describes the physical and logical recording formats  
used by the tape drives, including the implementation of  
helical-scan recording technology.  
Chapter 3 describes the functional features of the tape drives,  
including how they perform read and write operations.  
Chapter 4 lists the requirements for installing, operating,  
maintaining, and shipping the tape drives.  
Chapter 5 describes how the tape drives implement the Small  
Computer System Interface (SCSI), including an overview of SCSI  
messages and commands.  
Chapter 6 lists performance, reliability, power, and environmental  
specifications.  
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Chapter 7 describes compliance with regulatory and safety  
agency standards, including electromagnetic susceptibility (EMI),  
susceptibility to electrostatic discharge (ESD), and radiated  
susceptibility.  
This product specification contains a glossary and an index.  
Related Publications  
The following publications list additional, related information.  
EXB-8205 and EXB-8505 8mm Cartridge Tape Subsystems  
For information about installing, operating, and maintaining the  
EXB-8205, EXB-8205XL, EXB-8505, and EXB-8505XL, and for  
information about implementing SCSI commands, refer to the  
following publications:  
EXB-8205 and EXB-8505 8mm Cartridge Tape Subsystems SCSI  
Reference for Standard and eXtended Length Configurations,  
510503  
EXB-8205 and EXB-8505 8mm Cartridge Tape Subsystems  
Integration and Optimization for Standard and eXtended Length  
Configurations, 510505  
EXB-8205 and EXB-8505 8mm Cartridge Tape Subsystems  
Installation and Operation for Standard and eXtended Length  
Configurations, 302967  
Libraries and Enclosures  
For information about libraries and enclosures currently available for  
the EXB-8205, EXB-8205XL, EXB-8505, and EXB-8505XL, refer to the  
following publications:  
EXB-210 8mm Library Product Specification, 510807  
Mini Tabletop 8mm Cartridge Tape Subsystem Product  
Specification, 520154  
EXB-8205 and EXB-8505  
510504  
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Standards  
For information about the standards used for the tape drives, refer to  
the following publications:  
ANSI Small Computer System Interface (SCSI), X3.131 - 1989  
ANSI Small Computer System Interface-2 (SCSI-2), X3.131 -1994  
ANSI/ ISO/ IEC 11319-1992 and ECMA-145, Information  
Technology —8mm Wide Magnetic Tape Cartridge for  
Information Interchange, July 1992  
ISO/ IEC 12246 and ECMA-169, Information Technology—8mm  
Wide Magnetic Tape Cartridge Dual Azimuth Format for  
Information Interchange, Helical Scan Recording  
Conventions Used in This Specification  
This specification uses special conventions to highlight notes, important  
information, and cautions. These conventions are explained below.  
Note: Read Notes for hints or suggestions about the topic or procedure  
being discussed.  
Important Read Important text to learn crucial information about the  
topic or procedure being discussed.  
#
CAUTION  
Read the information in CAUTION boxes to learn ways to avoid  
damaging the equipment.  
May 1994  
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Notes:  
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1
Features  
This chapter provides an overview of the EXB-8205, EXB-8205XL,  
EXB-8505, and EXB-8505XL, including:  
Features  
Physical description  
Related products  
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1 Features  
Features  
The EXB-8205, EXB-8205XL, EXB-8505, and EXB-8505XL are enhanced  
8mm digital helical-scan cartridge tape subsystems (tape drives). The  
tape drives are packaged in the industry standard 5.25-inch half-high  
form factor, which allows for ease of integration across a multitude of  
platforms.  
Featuring an integral Small Computer System Interface (SCSI)  
controller (either single-ended or differential configuration), these  
tape drives are the easily integrated solution to your journaling,  
archiving, data interchange, software distribution, imaging, data  
acquisition, and backup/ restore needs.  
Note: This specification applies to the EXB-8205, EXB-8205XL,  
EXB-8505, and EXB-8505XL. However, most of the  
illustrations in this manual show the EXB-8505.  
In their compressed modes, the EXB-8205 can store up to 5 GBytes  
and the EXB-8505 can store up to 10 GBytes on a single 112m data  
cartridge, assuming an average compression ratio of 2:1.  
The eXtended-Length (XL) configurations of these tape drives  
provide additional capacity by supporting EXATAPE 160m XL 8mm  
Data Cartridges. Assuming an average compression ratio of 2:1, the  
EXB-8505XL can store up to 14 GBytes of data on a single 160m XL  
data cartridge. Assuming the same compression ratio, the  
EXB-8205XL can store up to 7 GBytes on a single data cartridge.  
For more information on EXATAPE data cartridge capacity, see  
page 1-8. For more information on EXATAPE data cartridges, see  
Important EXATAPE 160m XL 8mm Data Cartridges are only  
#
supported by the extended length tape drives (EXB-8205XL and  
EXB-8505XL). The standard tape drives (EXB-8205 and  
EXB-8505) cannot write on or read from 160m XL data cartridges  
and will automatically eject them.  
As shown in Figure 1-1, the four tape drive models look identical,  
except for minor differences in the LEDs and the unload button.  
1-2  
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1 Features  
Figure 1-1 Comparison of the four tape drives  
The EXB-8205XL and EXB-8505XL are fully compatible with the  
EXB-8205 and EXB-8505; each extended length tape drive supports all  
of the tape sizes and data formats supported by the corresponding  
standard tape drive. You can distinguish an extended length tape  
drive from a standard tape drive by checking the unload button. The  
extended length tape drives have a raised diamond pattern on the  
unload button.  
Table 1-1 compares the features of the tape drives.  
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1 Features  
Table 1-1 Comparison of tape drive features  
EXB-8505 and EXB-8505XL  
Half-high 5.25 inches  
8200, 8200c, 8500, 8500c  
1.0 MByte  
EXB-8205 and EXB-8205XL  
Form factor  
Data formats supported  
Buffer size  
8200, 8200c  
Data transfer rate*  
1.0 MByte per second  
500 KBytes per second  
75X normal (8500c, 8500, and  
8200c formats)  
75X normal (8200c format)  
10X normal (8200 format)  
Search speed  
10X normal (8200 format)  
Synchronous data transfer  
Time-to-clean LED indication  
Compression  
yes  
yes  
yes  
*These figures represent the maximum sustained data transfer rate, assuming a 2:1 data compression ratio.  
Read/Write Compatibility with Other Tape Drives  
The EXB-8205, EXB-8205XL, EXB-8505, and EXB-8505XL can read data  
cartridges written by other Exabyte 8mm tape drives, including the  
EXB-8200, the EXB-8200SX, the EXB-8500, and the EXB-8500c. They  
can also write on data cartridges that are intended for use with these  
other tape drives.  
Supported Formats  
The EXB-8505 and EXB-8505XL read and write data in four logical  
formats:  
8200  
8200c (compressed)  
8500  
8500c (compressed)  
The EXB-8205 and EXB-8205XL read and write data in two logical  
formats:  
8200  
8200c (compressed)  
Table 1-2 shows the read and write compatibility of the four logical  
data formats with the tape drives. Table 1-3 compares these data  
formats.  
1-4  
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1 Features  
Table 1-2 Read/write compatibility of Exabyte 8mm tape drives  
A tape  
Can be read and written by an ...  
written in  
this format...  
EXB-8205  
EXB-8205 XL  
EXB-8505  
EXB-8505 XL  
4
4
4
4
4
4
4
4
4
4
4
4
8200  
8200c  
8500  
8500c  
Table 1-3 Data format features  
8500 format  
(EXB-8505 and  
EXB-8505XL)  
8500c format*  
(EXB-8505 and  
EXB-8505XL)  
8200  
format  
8200c  
format*  
262  
KBytes/sec  
500  
KBytes/sec  
1.0  
MByte/sec  
Maximum sustained  
data transfer rate  
2.5  
GBytes  
5.0  
GBytes  
10.0  
GBytes  
Maximum capacity on  
112m tape  
Maximum capacity  
on 160m XL tape (XL  
configurations only)  
3.5  
GBytes  
7.0  
GBytes  
14.0  
GBytes  
Helical scan: Two write heads write  
two overlapping data tracks.  
Track 1 = +20° azimuth.  
Helical scan: One write head writes  
a single data track  
Track  
structure  
with a –10° azimuth.  
Track 2 = –10° azimuth.  
Supports partitions  
Supports setmarks  
Long filemarks  
no  
no  
yes  
yes  
270 tracks (2,160 KBytes)  
23 tracks  
6 tracks (48 KBytes)  
Short filemarks  
Setmarks  
one 1-KByte physical block  
(184 KBytes)  
yes–6 tracks  
(48 KBytes)  
no  
EOD mark  
no  
no  
yes–849 tracks  
yes–602 tracks  
Search fields  
yes  
yes  
Logical  
block packing  
no  
*Assumes a data compression ratio of 2:1.  
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1 Features  
Determining the Tape Format  
When writing data to tape, the tape drive does one of the following:  
If the tape is positioned at the logical beginning of tape (LBOT),  
the tape drive writes data in the default format or whatever  
format you select with the SCSI MODE SELECT (15h) command.  
(The tape drive allows only one format on any one tape.)  
If the tape is positioned at any other valid position for writing  
data, the tape drive writes data in the same format as the data  
already on the tape.  
When reading a data cartridge, the tape drive automatically  
determines the tapes format.  
Data Compression  
When the tape drive compresses data, it uses the established  
Improved Data Recording Capability (IDRC) algorithm. Licensed  
from IBM, this algorithm is the de facto standard in mainframe  
environments. The tape drives also use the Exabyte Compression  
Integrity Check™ feature to ensure that data is accurately compressed  
and decompressed into the original form sent by the initiator.  
The compression algorithm is completely contained in an Exabyte  
proprietary integrated circuit. The tape drive invokes the compression  
algorithm intelligently, constantly monitoring the compression ratio  
to determine whether compressing the data will actually decrease the  
size of the data set. The tape drive sends compressed data to tape only  
when it benefits the users storage capacity and throughput.  
Although the actual data compression ratio depends on the type of  
data, the EXB-8205, EXB-8205XL, EXB-8505, and EXB-8505XL achieve  
an average compression ratio of 2:1.  
For detailed information about how the tape drives compress data,  
1-6  
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1 Features  
Custom EEPROM Options  
When the tape drive is manufactured, a number of operating features  
and default values are programmed in the electronically erasable  
programmable read-only memory (EEPROM). These operating  
features and default values, called EEPROM options, include such  
items as MODE SELECT power-on default values, command set  
options, hardware operation options, and SCSI configuration options.  
When you order a tape drive, you can contact an Exabyte account  
manager to select which, if any, EEPROM settings you want to change  
from their standard settings. Using this information, Exabyte can  
create a customized EEPROM image that meets your integration and  
application development needs. Once your designated EEPROM  
structure is released, each tape drive you purchase will be  
factory-configured to your specifications.  
Note: You can use the CTS Monitor program to change some of the  
tape drives EEPROM option settings. For more information  
about these options, refer to the documentation for the CTS  
Monitor program.  
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1 Features  
Storage Capacity  
Table 1-4 lists the approximate storage capacities of 8mm data  
cartridges written in the four logical formats. For more information  
on EXATAPE 8mm data cartridges, see page 1-20.  
Table 1-4 Approximate capacities of EXATAPE data cartridges  
a
Length of  
EXATAPE  
Approximate Capacity to LEOT in MBytes  
8500c  
compressed  
8500 format  
(EXB-8505 and  
EXB-8505XL)  
8200c  
b
format  
(EXB-8505 and  
EXB-8505XL)  
compressed  
8200 format  
b
format  
15m  
54m  
112m  
1,176  
4,697  
9,888  
14,000  
588  
588  
294  
2,348  
4,944  
7,000  
2,348  
4,698  
7,000  
1,174  
2,349  
3,500  
c
160m XL  
a Logical end of tape.  
b These columns assume an average compression ratio of 2:1 (on average, each compressed 1,024-byte  
physical block represents 2,048 bytes of user data).  
c EXATAPE 160m XL extended length media is compatible with the EXB-8205XL and EXB-8505XL only.  
1-8  
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1 Features  
Physical Description  
This section describes the physical features of the tape drive,  
including the following:  
External features  
Size and weight  
Internal components  
Front Panel Controls and Indicators  
Figure 1-2 shows the controls and indicators on the front panel of the  
tape drive.  
Figure 1-2 Front panel  
Door and Bezel  
Standard colors for the door and bezel include black, pearl white,  
pebble gray, platinum, and gray. Exabyte can provide custom colors  
at an additional cost. (Contact your account manager for more  
information.)  
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1 Features  
Unload Button  
The unload button is the only operator control on the tape drive.  
Pushing this button starts the unload procedure. On the EXB-8205  
and EXB-8505, the unload button is smooth and has an oval-shaped  
indentation. On the EXB-8205XL and EXB-8505XL, the unload button  
has a diamond texture.  
See Chapter 4 for more information about loading and unloading  
cartridges.  
LEDs  
The tape drive contains three LEDs on the front panel. Various  
combinations of these LEDs (either on, off, or flashing) indicate the  
status of the tape drive operations. See Chapter 4 for more  
information about the LED functions.  
Labels  
All Exabyte products are required to include standard process,  
configuration, and agency labels. Figure 1-3 shows the location and  
content of these labels on the top cover of the tape drive.  
Figure 1-3 Label location and content  
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1 Features  
Back Panel Components  
Figure 1-4 shows the back panel of a single-ended tape drive. The  
differential tape drives look similar except that there are no SCSI  
terminator R-packs (resistor terminators).  
Figure 1-4 Back panel (single-ended configuration)  
Ground Tab and Grounding Hole  
The tape drive includes a ground tab and grounding hole to use if  
you want additional chassis grounding. See Chapter 6 for more  
information.  
SCSI Connector  
The 50-pin SCSI connector on the tape drive allows you to connect the  
tape drive to the SCSI bus. Pin 1 is the first pin on the right side of the  
top row.  
See Chapter 5 for more information about connecting the tape drive to  
the SCSI bus.  
Power Connector  
The 4-pin power connector on the tape drive is compatible with the  
power connector used for standard 5.25-inch half-high devices. See  
Chapter 6 for more information.  
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1 Features  
SCSI ID Jumper Block  
The SCSI ID jumper block on the tape drive enables you to set the  
SCSI ID either by using a remote switch or by installing jumpers. See  
Chapter 4 for more information about setting the SCSI ID.  
Monitor Port  
Using the Monitor port, you can change some of the tape drives  
configuration options, download code updates, and perform  
diagnostic procedures on the tape drive.  
To use the Monitor port, you will need the Exabyte CTS Monitor  
®
program and an IBM AT , XT™, or compatible system with a serial  
port.  
If your tape drive has a 3-pin Monitor port, you will need the  
following cables and connectors:  
A 3-pin to RJ-11 modular phone plug cable (Exabyte part number  
303772)  
An RJ-11 to 9-pin level shifter (Exabyte part number 301001)  
A 9-pin to 25-pin adapter cable (if your computer system has a  
25-pin serial port)  
If your tape drive has a 4-pin Monitor port, you will need the  
following cables and connectors:  
A 4-pin to 25-pin connector cable (Exabyte part number 727005)  
A 25-pin to 9-pin adapter cable (if your computer system has a  
9-pin serial port)  
Resistor Terminators (single-ended configuration only)  
The single-ended configuration of the EXB-8205 or EXB-8505 includes  
three single inline package (SIP) resistor terminators (R-packs) that  
you can use if the tape drive is the terminating device for the SCSI  
bus. You can remove these terminators if the tape drive does not  
terminate the bus or if you want to use external terminators. The first  
pin is on the right end of the terminator.  
Note: The differential configuration of the tape drive does not  
include internal terminators and must be terminated  
externally.  
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1 Features  
Internal Components of the Tape Drive  
This section describes the internal components of the tape drive,  
including the tape transport mechanism, the rotating drum assembly,  
and each of the four main cards.  
Figure 1-5 shows the internal components of the EXB-8505 and  
EXB-8505XL. The EXB-8205 and EXB-8205XL have a VUA card  
instead of the SUA card shown below.  
Figure 1-5 Internal components (EXB-8505 shown)  
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1 Features  
Tape Transport Mechanism  
The 8mm tape transport mechanism is manufactured by Sony to  
Exabyte specifications. It is compatible with 8mm data cartridges that  
meet the ECMA-145 standard.  
Rotating Drum Assembly  
The rotating drum assembly in the EXB-8205 and EXB-8205XL has  
one write head, one read head, and one servo head. The rotating  
drum assembly in the EXB-8505 and EXB-8505XL has five heads: two  
write heads (W1, W2), two read heads (R1, R2), and one servo head.  
Figure 1-6 shows the location of the heads on the EXB-8505 and  
EXB-8505XL drum assembly.  
Figure 1-6 Location of the read heads and write heads (EXB-8505)  
In the EXB-8505 and EXB-8505XL, the write and read heads can write  
and read two tracks of information simultaneously.  
The servo head is used for reading servo data, which enables the tape  
drive to control linear tape velocity to ensure accurate positioning of  
the read heads over the tape.  
1-14  
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1 Features  
The drum rotates constantly at 1831 rpm in the default format (8500c  
format for the EXB-8505 and EXB-8505XL; 8200c format for the  
EXB-8205 and EXB-8205XL). This speed of rotation results in a  
nominal effective head-to-tape speed of approximately 150.5 inches  
per second (3.8 meters per second). Approximate tape movement is  
0.5 inches per second (11.1 millimeters per second). Forces acting on  
the tape and various component mechanisms are correspondingly  
low, resulting in long life for both the media and tape transport  
mechanism.  
Note: In 8200 format, the drum rotates at 1923 rpm.  
Servo Card (SSV)  
The Servo (SSV) card contains the tape drives servo circuits,  
including two digital LSIs and one analog LSI, a dedicated  
6303-compatible microprocessor, and a 64-KByte FEPROM.  
The Servo card controls all the mechanics of the tape drive, such as  
the following:  
Tape transport mechanism  
Adjustment of tape velocity based on track-embedded servo  
information  
Drum, reel, and capstan servos  
Circuits that control the reel motor, the load motor, the drum and  
capstan motors, and the front load motor  
Sensor interface circuits for the drum, reel, and capstan,  
tachometers  
Sensor interface circuits for the load and mode states  
Sensor interface circuits for detecting physical beginning of tape  
(PBOT), physical end of tape (PEOT), tape length and type, and  
write protect and cartridge load states  
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1-15  
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1 Features  
Preamp and Upper Analog Cards  
A Preamp card (SPR card) contains preamplifier, motor, and write  
driver circuitry.  
The Upper Analog card (SUA card in the EXB-8505 and EXB-8505XL;  
VUA card in the EXB-8205 and EXB-8205XL) contains analog filters,  
equalization, and clock-detect circuitry.  
Together, the preamp and upper analog cards comprise the write and  
read electronics. The write electronics consist of write control circuits  
for digital data and servo information, as well as the write head driver  
circuits. The read electronics consist of preamplifiers and equalization  
circuits for the read channels, the servo channel, amplitude sensing,  
and data clocking and detection.  
Lower Digital (SLD) Card  
The Lower Digital (SLD) card contains the data processor, error  
correction code, buffer memory, and control circuitry. The tape  
drives data buffer includes 1 MByte of dynamic random access  
memory (DRAM).  
The SLD card controls communication between the tape drive and the  
SCSI bus, and can be either of the following:  
SLDS (single-ended SCSI)  
SLDD (differential SCSI)  
The SLD card contains a 8051-compatible microprocessor, which  
implements the controller function. The controller function includes  
the following activities:  
Data compression  
SCSI bus management  
SCSI command decode and status presentation  
Scheduling of all tape drive operations  
Motion control management  
Data transfer and buffer management  
Logical-to-physical block packing and unpacking  
Tape formatting; header and search field generation  
Read-after-write verification and rewrite management  
Tape drive statistics and sense data  
Error recovery procedures  
Monitor interface  
1-megabyte buffer  
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1 Features  
Size and Weight  
Designed to meet industry-standard 5.25-inch half-high form factor  
mounting requirements, the tape drive is 1.62 inches high × 5.75  
inches wide × 8.00 inches deep (41.2 × 146.0 × 203.2 mm) and weigh  
2.6 pounds (1.2 kilograms). Figure 1-7 shows the external dimensions  
of the tape drive.  
For information about mounting requirements, see Chapter 4.  
Figure 1-7 External dimensions in inches (and millimeters)  
May 1994  
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1-17  
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1 Features  
Related Products  
This section describes products related to the tape drives.  
Integration with Other Exabyte Products  
You can purchase the tape drive separately or already integrated with  
one of the following Exabyte products:  
EXB-210 8mm Library  
Mini Tabletop Cartridge Tape Subsystem  
EXB-210 8mm Library  
The EXB-210 is an 8mm data cartridge library that contains one or two  
half-high 8mm tape drives, a ten-cartridge magazine, one fixed  
cartridge slot, and a robotic handler. The robotic handler moves the  
8mm cartridges between the cartridge storage locations and the tape  
drives, greatly reducing the need for manual intervention.  
Figure 1-8 shows vertical (stand-alone) and horizontal (rack-mount)  
models of the EXB-210.  
Figure 1-8 EXB-210 8mm Library  
1-18  
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1 Features  
Designed as an easily integrated data management solution, the  
EXB-210 provides automated data storage in a SCSI-2 environment.  
Operating with an EXB-8505XL and assuming a data compression  
ratio of 2:1, the EXB-210 can store up to 154 GBytes on eleven  
160m XL data cartridges.  
For more information about the EXB-210, refer to the EXB-210 8mm  
Library Product Specification.  
Mini Tabletop Cartridge Tape Subsystem  
The Mini Tabletop Cartridge Tape Subsystem (Mini Tabletop CTS) is  
an 8mm tape drive enclosure, which includes a power supply,  
thermistor-controlled fan, SCSI connectors, and Monitor port.  
Figure 1-9 shows vertical, horizontal, front, and back views of the  
Mini Tabletop CTS.  
Figure 1-9 Mini Tabletop CTSs with EXB-8505s installed  
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1 Features  
The Mini Tabletop CTS is lightweight and completely enclosed. It has  
an internal, self-switching universal power supply, which allows  
continuous operation during limited power interruptions or surges.  
The Mini Tabletop CTS also offers maximum EMI/ RFI shielding.  
A remote SCSI ID switch and two SCSI connectors on the enclosure  
provide multiple options in a daisy-chained environment.  
For more information about the Mini Tabletop CTS, refer to the Mini  
Tabletop Cartridge Tape Subsystem Product Specification.  
EXATAPEÔ Data Cartridges  
The tape drives use data-quality removable, rewriteable 8mm  
metal-particle data cartridges. These data cartridges require no  
formatting or other media conditioning before use.  
Important Exabyte strongly recommends that you use EXATAPE  
#
data-grade media with all Exabyte products, including the  
EXB-8205, EXB-8205XL, EXB-8505, and EXB-8505XL. EXATAPE  
media meets specifications that are the most stringent in the  
industry.  
Unlike media available from other manufacturers, EXATAPE media  
is specifically controlled for use in a data storage environment and  
offers reliability, extended durability, and long-term archivability. In  
addition, exclusive use of EXATAPE media with Exabyte 8mm tape  
drives has been shown to prolong head and tape life.  
Table 1-5 shows EXATAPE data cartridge compatibility with Exabyte  
half-high and full-high drives.  
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1 Features  
Table 1-5 EXATAPE media compatibility with 8mm tape drives  
EXATAPE Thickness  
Length  
Compatible 8mm Tape Drives  
EXB-8205XL  
and  
EXB-8505XL  
EXB-8200 and  
EXB-8200SX  
EXB-8500 and  
EXB-8500c  
EXB-8205 and  
EXB-8505  
4
4
4
4
4
4
4
4
4
4
4
4
15m  
54m  
112m  
13 µm  
13 µm  
10 µm  
4
Do not use  
Do not use  
Automatically  
ejects  
7.7 µm  
160m XL  
Important EXATAPE 160m XL media is compatible with the  
EXB-8205XL and EXB-8505XL only. The EXB-8205 and EXB-8505  
will automatically eject these data cartridges.  
#
Although Exabyte full-high 8mm tape drives will accept EXATAPE  
160m XL data cartridges, they are not compatible and should not  
be used together.  
EXATAPE 160m XL data cartridges offer the same reliability and  
performance as all other EXATAPE data cartridges.  
All EXATAPE 160m XL data cartridges contain a single Recognition  
System stripe located on the tape leader for media identification. The  
EXB-8205XL and EXB-8505XL are capable of detecting this stripe,  
which they use to distinguish data-quality metal-particle media, such  
as EXATAPE, from other 160m media.  
To maintain data integrity, the EXB-8205XL and EXB-8505XL  
automatically eject 160m data cartridges or equivalent length video  
cartridges that are not equipped with the Recognition System stripe.  
By rejecting potentially inferior media, the extended length tape  
drives ensure greater data reliability and protect the read and write  
heads from unnecessary wear.  
May 1994  
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1-21  
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1 Features  
Exabyte Cleaning Cartridges  
Use an Exabyte 8mm Cleaning Cartridge to clean the tape drive. The  
Exabyte 8mm Cleaning Cartridge contains a shed-free fabric tape that  
traps and removes debris from tape drive heads and tape paths. By  
using this cleaning cartridge on a regular basis, you maintain data  
integrity and improve reliability of the tape drive.  
Exabyte 8mm Cleaning Cartridges come in two sizes: 3c and 12c.  
Used in a half-high tape drive, the 3c cartridge offers up to 9 cleaning  
passes, and the 12c cartridge can offer as many as 36 cleaning passes.  
Details on the cleaning intervals are given in Chapter 4.  
Note: If you are using these cleaning cartridges with Exabyte  
full-high 8mm tape drives, you will get fewer cleaning passes  
per cartridge. Because full-high tape drives have a longer tape  
path, more material is required for each cleaning.  
CAUTION  
The Exabyte 8mm Cleaning Cartridge (or an Exabyte-approved  
cleaning cartridge) is the only authorized method for cleaning the  
tape drive. Other 8mm cleaning kits can leave fragments in the  
tape path or on the heads. If you use any other type of cleaning  
material, you will void the tape drive warranty.  
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2
Recording Format  
This chapter describes the recording formats used by the EXB-8205,  
EXB-8205XL, EXB-8505, and EXB-8505XL. It includes information  
about the following:  
Helical-scan recording  
Physical format of the recorded tape  
Logical format of the recorded tape  
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2 Recording Format  
Helical-Scan Recording  
To increase the amount of data that can be recorded on the tape, the  
tape drive implements advanced helical-scan recording technology.  
Helical-scan recorders write very narrow tracks at an acute angle to  
the edge of the tape, as shown in Figure 2-1. This recording method  
creates a track length that is several times longer than the width of the  
tape. Tracks can be accurately positioned by the geometry of the tape  
path to precise minimal tolerances, resulting in a very high number of  
tracks per inch.  
The combination of the helical wrap of the tape around the drum, the  
rotation of the head/ drum assembly, and the linear motion of the  
tape causes the heads to trace a track across the tape that is 2.47 inches  
(62.7 millimeters) long, at an acute angle of approximately 5 degrees  
to the bottom edge of the tape.  
Figure 2-1 Helical-scan recording  
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2 Recording Format  
Physical Format  
This section defines the physical track structure of the tape, including  
the types of physical track structures, physical blocks, search fields,  
and servo areas.  
Physical Track Structure  
The EXB-8205 and EXB-8205XL can write data to tape in two types of  
physical track structures: 8200 and 8200c. The EXB-8505 and  
EXB-8505XL can write data to tape in three types of physical track  
structures: 8500/ 8500c, 8200c, and 8200. These track structures are  
described below. Figure 2-2 shows the relationship between the three  
physical track structures and the four logical data formats.  
In 8500/8500c track structure, the tape drive writes two  
overlapping tracks to the tape for each revolution of the drum.  
Each track contains data blocks, servo areas (track 2 only), clock  
sync areas, and search fields. 8500/ 8500c track structure is also  
called dual-azimuth track structure.  
Note: 8500 and 8500c physical track structures are identical. Using  
the compressed logical format (8500c), the EXB-8505 and  
EXB-8505XL compress data before storing it in physical  
blocks. Using the uncompressed logical format (8500), the  
tape drives do not compress data.  
In 8200c track structure, the tape drive writes a single track to the  
tape for each revolution of the drum. Like 8500/ 8500c tracks, each  
track contains data blocks, servo areas, clock sync areas, and  
search fields. 8200c track structure is also called single-azimuth  
compressed track structure.  
In 8200 track structure, the tape drive writes a single track to tape  
for each revolution of the drum. Each track contains data blocks  
and one servo area for accurate positioning of the tape. 8200 track  
structure is also called single-azimuth uncompressed track structure.  
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2 Recording Format  
Figure 2-2 Relationship of 8mm physical track structures to logical data formats  
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2 Recording Format  
8500/8500c Physical Track Structure  
In 8500/ 8500c format, an EXB-8505 or EXB-8505XL uses the W1 and  
W2 heads to write two partially overlapping physical tracks on the  
tape for each revolution of its head/ drum assembly. The width of  
each track is 15.5 µm. During a read operation, the tape drive uses the  
R1 and R2 heads to read the two tracks.  
Figure 2-3 shows the physical track structure on a tape written in 8500  
and 8500c format.  
Figure 2-3 Physical track structure for 8500 and 8500c format  
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2 Recording Format  
Figure 2-4 shows the position of the EXB-8505 and EXB-8505XL’s  
write (W1, W2), read (R1, R2), and servo heads, relative to the tracks  
as the heads pass across the tape when the tape drive is writing or  
reading 8500 and 8500c format tapes.  
Figure 2-4 Position of the tape drive’s heads relative to the tracks (8500/8500c format)  
8200c and 8200 Physical Track Structure  
In 8200c and 8200 formats, the tape drive writes one physical track on  
the tape for each revolution of the head/ drum assembly. The width of  
the track is 25 µm. During a read operation, the tape drive reads a  
single track. The EXB-8505 and EXB-8505XL use the W2 write head  
and R2 read head for these operations.  
Figure 2-5 shows the physical track structure on a tape written in  
8200c format. Figure 2-6 shows the physical track structure on a tape  
written in 8200 format.  
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2 Recording Format  
Figure 2-5 Physical track structure for 8200c track format  
Figure 2-6 Physical track structure for 8200 track format  
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2 Recording Format  
Figure 2-7 shows the position of the tape drives write head, read  
head, and servo head relative to the tracks as the heads pass across  
the tape when the tape drive is reading and writing 8200c format  
tapes. (For the EXB-8505 and EXB-8505XL, the W2 write head and R2  
read head positions are shown.)  
Figure 2-7 Position of the tape drive’s heads relative to the tracks (8200c format)  
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2 Recording Format  
Physical Blocks  
For all three physical track formats, each physical track contains eight  
physical blocks. A physical block can contain user data or other  
information. As shown in Figure 2-8, a physical block containing user  
data includes the following information:  
2 bytes of cyclic redundancy check (CRC) data  
400 bytes of error correction code (ECC) data  
1,024 bytes of uncompressed user data or 2,048 of compressed  
user data (assuming a 2:1 compression efficiency)  
14 bytes of header information  
Figure 2-8 Physical block format for all logical formats (8200c or 8500/8500c physical track structure shown)  
Note: The physical block header, ECC data, and physical block CRC  
data do not affect the data capacity of the tape.  
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2 Recording Format  
Search Fields  
For 8500/ 8500c and 8200c track structures, each track contains search  
fields used for high-speed search. (Figure 2-8 shows where search  
fields are located in a track.) The search fields are the only areas of the  
tape that are read during a high-speed search. The search field data  
contains information for locating files and blocks and detecting the  
end-of-data (EOD) mark during high-speed searches.  
Note: Tapes written in 8200 format are SCSI-1 compatible and do  
not contain search fields. For this reason, 8200 format tapes do  
not support high-speed search. In addition, the EXB-8205,  
EXB-8205XL, EXB-8505, and EXB-8505XL do not support the  
EXB-8200SX high-speed search feature.  
Servo Areas  
For all three physical track structures, each track contains servo areas  
that the tape drive uses to read tapes written by other tape drives.  
Each servo area contains a signal that the servo head detects and uses  
to control linear tape velocity. This track-following servo process  
results in accurate positioning of the track under the read head.  
The servo scheme is based on the geometry of the track positions.  
Each servo area consists of one servo data signal burst surrounded by  
an erase (margin) signal. The tape drive places servo areas in the  
following locations, based on physical track format:  
In 8200 format, the tape drive places a servo area at the beginning  
of each track (as shown in Figure 2-6).  
In 8200c format, the tape drive places a servo area at the  
beginning, middle, and end of every track (as shown in  
Figure 2-7).  
In 8500/ 8500c format, the tape drive places a servo area at the  
beginning, middle, and end of every other track (as shown in  
Figure 2-4).  
Note: Refer to the EXB-8200 8mm Cartridge Tape Subsystem Product  
Specification for information about track-following servo for  
8200 format.  
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2 Recording Format  
Recording Parameters  
Table 2-1 shows the recording parameters for the EXB-8205,  
EXB-8205XL, EXB-8505, and EXB-8505XL. The table includes the  
parameters for tape drives writing and reading data in three physical  
formats.  
Table 2-1 Recording parameters  
Tape drives reading and writing in this physical format:  
Parameter  
a
8500/8500c  
8200c  
8200  
Tape width  
8.00 mm  
(0.315 in)  
8.00 mm  
(0.315 in)  
8.00 mm  
(0.315 in)  
Track length  
(data + servo)  
62.651 mm  
(2.47 in.)  
62.651 mm  
(2.47 in)  
71.628 mm  
(2.82 in)  
b
Tracks per  
revolution  
2
1
1
c
Track pitch  
Track width  
Track density  
15.5 µm  
(0.000610 in)  
31.0 µm  
(0.001221 in)  
31.0 µm  
(0.001221 in)  
15.5 µm  
(0.000610 in)  
25.0 µm  
(0.000984 in)  
25.0 µm.  
(0.000984 in)  
64.506 trk/mm  
(1638.455 trk/in)  
32.253 trk/mm  
(819.226 trk/in)  
32.254 trk/mm  
(819.253 trk/in)  
2
2
2
Areal recording  
density  
144.23 Mfc/mm  
72.115 Mfc/mm  
68.68 Mfc/mm  
2
2
2
(93.052 Mfc/in )  
(46.526 Mfc/in )  
(44.312 Mfc/in )  
Drum speed  
Tape speed  
1831.055 rpm  
1831.055 rpm  
1922.607 rpm  
11.079 mm/sec  
(0.436 ips)  
11.079 mm/sec  
(0.436 ips)  
11.633 mm/sec  
(0.458 ips)  
Track angle  
Wrap angle  
4.9 degrees  
221 degrees  
4.9 degrees  
221 degrees  
4.9 degrees  
221 degrees  
a EXB-8505 and EXB-8505XL only.  
b In 8200c and 8500/8500c formats, servo information is embedded in three places along the length of the track.  
In 8200 format, servo information is embedded at the beginning of the track.  
c Tracks per revolution is the number of tracks written or read for each revolution of the rotating drum assembly.  
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2 Recording Format  
Logical Format  
The following sections describe the logical characteristics of the  
information recorded on the tape. The logical tape format consists of  
the logical beginning of tape (LBOT) mark, followed by any number  
of tracks up to the limit for the data cartridge. These tracks can  
include logical blocks of data, gap blocks and gap bytes, filemarks,  
setmarks, and end-of-data information.  
Supported Logical Formats  
The EXB-8205 and EXB-8205XL can write user data in the following  
logical tape formats:  
8200c (compressed)  
8200  
The EXB-8505 and EXB-8505XL can write user data in any of the  
following logical tape formats:  
8500c (compressed)  
8500  
8200c (compressed)  
8200  
See Figure 2-2 for information about the correspondence between  
logical tape formats and physical formats.  
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2 Recording Format  
Logical Blocks  
A logical block contains user data that is transferred from the host to  
the tape drive. Logical blocks can have fixed or variable lengths,  
which can be intermixed on the tape. The tape drive supports  
uncompressed logical block sizes from 1 to 240 KBytes.  
For information about setting the logical block size, refer to the  
EXB-8205 and EXB-8505 SCSI Reference.  
Logical Block Compression  
When writing data in 8500c and 8200c formats, the tape drive  
compresses logical blocks of user data before placing them in the  
physical blocks. Thus, each physical block contains a compressed  
representation of the original user data. Assuming that the  
compression algorithm allows user data to be compressed an average  
of two times, each physical block written by the tape drive in  
compressed format can contain, on average, the compressed  
equivalent of 2,048 bytes of user data.  
Note: The actual compression ratio achieved by the tape drive in  
8500c and 8200c formats depends on the type of data to be  
compressed.  
For more information about compression, refer to Chapter 3.  
Logical Block Packing  
To optimize tape capacity when writing tapes in 8200c, 8500, or 8500c  
formats, the tape drive packs logical blocks of user data into physical  
blocks. Each 1,024-byte physical block on tape can contain multiple  
logical blocks (for example, two 512-byte uncompressed logical blocks  
can be written in one physical block). To prevent losing data capacity  
when small logical block sizes are used, the tape drive can begin  
writing a logical block in one physical block and end in a subsequent  
physical block.  
Note: In 8200 format, logical blocks are not packed. Only one or  
part of one logical block can be written in each physical block.  
Figure 2-9 shows three examples of how logical blocks can be written  
into one 1,024-byte physical block.  
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2 Recording Format  
In 8200 format, each physical block contains one header and one  
logical block. In 8200c, 8500, and 8500c formats, each physical block  
includes a 14-byte header that can define only two logical blocks. If  
the physical block contains more than two logical blocks, the tape  
drive adds an additional two-byte header in the data field for each  
logical block after the second one.  
Header and 1 logical block  
8200 format:  
Header  
1,024 bytes  
Header and 2 logical blocks  
Other formats:  
Header  
Header  
512 bytes  
512 bytes  
Header, 2 logical blocks, header, 1 logical block, and free space  
256 bytes 256 bytes 256 bytes 254 bytes free  
2-byte header  
Figure 2-9 Logical block packing (one physical block)  
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2 Recording Format  
Gap Bytes  
A gap byte is a byte containing undefined data that the tape drive uses  
to fill empty space in a physical block. The tape drive may  
automatically write gap bytes in the following cases:  
At the end of a write operation.  
Before writing a filemark.  
Before writing a setmark (EXB-8505 or EXB-8505XL only).  
When it is physically impossible to start the next logical block in  
the physical block because less than three bytes are available.  
(This is because the two-byte header and at least one data byte  
must be present in the first physical block before the logical block  
can spill over to a second physical block.)  
Figure 2-10 shows how gap bytes can be used to fill empty space at  
the end of a physical block. Gap bytes cannot be accessed by any SCSI  
command.  
Header, 2 logical blocks, header, 2 logical blocks, and 2 gap bytes  
256 bytes  
256 bytes  
256 bytes  
250 bytes  
14-byte header  
2-byte headers  
2 gap bytes  
Figure 2-10 Gap bytes (one physical block)  
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2 Recording Format  
Gap Blocks and Gap Tracks  
A gap block is a physical block containing 1,024 gap bytes. A gap track  
is a physical track containing eight gap blocks. When the tape drive  
stops at the end of a write operation, it writes at least one gap track  
following the last track containing data blocks. In 8200 or 8200c  
format, the tape drive writes one gap track. In 8500 or 8500c format, it  
can write two gap tracks.  
The gap track provides the track orientation required to append data.  
When a subsequent write operation begins, the controller repositions  
the tape and records the data on a track adjacent to the gap track.  
Figure 2-11 shows two tracks, one with seven data blocks and one gap  
block, and one with a gap track. Gap blocks cannot be accessed by  
any SCSI command.  
1 gap track  
7 data blocks  
1 gap block  
Figure 2-11 One gap block and one gap track in two physical tracks  
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2 Recording Format  
Filemarks  
Filemarks enable the initiator to locate particular blocks of data on the  
tape quickly during a high-speed search. By using a SPACE filemark  
(11h) command, the initiator can position the tape to the data marked  
by filemarks at up to 75 times the normal tape speed (or up to 10  
times the normal tape speed when reading an 8200 format tape).  
Depending on the format, the tape drive can write either a long or  
short filemark. Table 2-2 shows the type and size of filemarks for each  
format type.  
Table 2-2 Type and size of filemarks for each format  
Type and size of filemarks  
Tape format  
Long filemark  
(KBytes)  
Short filemark  
(KBytes)  
8500 or  
8500c  
48  
1
8200  
2,160  
2,160  
184  
1
8200c  
Long Filemarks  
A long filemark in either 8500 or 8500c format consists of six tracks of  
information:  
Two gap tracks at the beginning  
Two tracks of filemark physical blocks  
Two gap tracks at the end  
A long filemark in 8200c or 8200 format consists of the following:  
An erase gap equivalent in length to 249 tracks  
21 tracks (168 blocks) of long filemark physical blocks  
The information in the filemark physical blocks identifies the  
filemarks number and location on the tape and cannot be accessed or  
changed by the user. The gap tracks at the beginning and end allow  
file append and file splice operations. The tape drive may write  
additional gap tracks and gap blocks before the filemark to ensure  
that all data has been written to tape correctly or to complete tracks  
that are not completely filled with data blocks.  
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2 Recording Format  
Short Filemarks  
In 8500, 8500c, and 8200c formats, a short filemark consists of a single,  
1-KByte physical block. This block contains information identifying  
the filemarks number and location on the tape.  
In 8200 format, a short filemark consists of 21 tracks of information.  
Setmarks (EXB-8505 and EXB-8505XL only)  
When the EXB-8505 or EXB-8505XL is writing in 8500c format, you  
can issue a WRITE FILEMARKS (10h) command to write one or more  
setmarks to tape. Setmarks provide an additional way to indicate data  
boundaries on the tape; in a sense, they can be thought of as  
“hierarchically superior” filemarks.  
Each setmark is 48 KBytes long and consists of the following:  
Two gap tracks at the beginning  
Two tracks of setmark physical blocks  
Two gap tracks at the end  
You can issue a SPACE (11h) command to space to setmarks;  
however, you can also use a MODE SELECT (15h) command to  
suppress setmark detection during read, verify, space block, and  
space filemark operations.  
End of Data(EOD)  
When writing tapes in 8500, 8500c, or 8200c format, the tape drive  
writes an end-of-data (EOD) mark after the last data written to tape.  
In 8500 and 8500c formats, the EOD mark consists of one or more gap  
tracks, erase gaps, and 600 tracks of end-of-data blocks. In 8200c  
format, the EOD mark consists of 249 erase gap tracks and 600 tracks  
of end-of-data blocks.  
These tracks are used when the initiator issues a SPACE (11h)  
command to locate the last data written to tape. The tape drive  
overwrites the EOD mark when it writes additional data to tape.  
In 8200 format, there is no EOD mark, but you can space to the end of  
data.  
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2 Recording Format  
Track and Block Counts  
The number of tracks and physical blocks on the tape depend on the  
following markers:  
Physical beginning of tape (PBOT). PBOT is located at the point  
on the tape where the translucent leader material is attached to  
the media. This position is detected by an optical sensor in the  
tape transport mechanism.  
Logical beginning of tape (LBOT). When you issue a write  
operation at the beginning of tape, the tape drive automatically  
records LBOT at approximately 29 inches (74 cm) from PBOT. The  
LBOT area includes tracks of LBOT information, which are used  
to indicate the LBOTs location, to calibrate the servo system and  
to indicate whether the tape was written in uncompressed or  
compressed format. The data contained in the LBOT blocks  
cannot be altered or accessed by the user.  
Logical end of tape (LEOT). LEOT is determined by the number  
of recorded tracks that occur after LBOT. For this purpose,  
lengths of erased segments are converted into an equivalent  
number of tracks.  
Physical end of tape (PEOT). PEOT is located at the point on the  
tape where the translucent trailer material is attached to the  
media. This position is detected by an optical sensor in the tape  
transport mechanism.  
The number of tracks between LBOT and LEOT depends on the type  
and length of tape. Table 2-3 and Table 2-4 list the following  
information for tapes written in various formats:  
The number of tracks and 1,024-byte physical blocks between  
LBOT and LEOT  
The approximate number of tracks and 1,024-byte physical blocks  
that occur between LEOT and PEOT  
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2 Recording Format  
Table 2-3 Track and physical block counts for 8200 and 8200c formats  
LBOT to LEOT  
EXATAPE  
LEOT to PEOT*  
Number of tracks Number of blocks  
Number of tracks  
Number of blocks  
Hex Decimal  
46220h 287,264  
Size  
Hex  
Decimal  
Hex  
Decimal  
4,521  
Hex  
Decimal  
36,168  
35,440  
142,720  
52,612  
15m  
54m  
8C44h  
35,908  
11A9h  
8D48h  
8A70h  
22D8h  
CD84h  
22FF2h 143,346 117F90h 1,146,768 114Eh  
46000h 286,720 230000h 2,293,760 45B0h  
696F9h 431,865 34B7C8h 3,454,920 19B0h  
4,430  
112m  
17,840  
6,576  
160m XL  
*Track and block counts from LEOT to PEOT are approximate.  
Table 2-4 Track and physical block counts for 8500 and 8500c formats  
LBOT to LEOT  
EXATAPE  
LEOT to PEOT*  
Number of tracks Number of blocks  
Number of tracks  
Number of blocks  
Hex Decimal  
8C440h 574,528  
Size  
Hex  
Decimal  
Hex  
Decimal  
2,388  
Hex  
Decimal  
19,104  
70,896  
70,928  
15m  
54m  
11888h  
71,816  
954h  
4AA0h  
114F0h  
11510h  
45FE4h 286,692 22FF20h 2,293,536 229Eh  
93568h 603,496 49AB40h 4,827,968 22A2h  
8,862  
112m  
8,866  
160m XL D2DF2h 863,730 696F90h 6,909,840 3361h  
*Track and block counts from LEOT to PEOT are approximate.  
13,153  
19B08h 105,224  
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3
Functional Description  
This chapter describes the functional features of the EXB-8205,  
EXB-8205XL, EXB-8505, and EXB-8505XL, including write and read  
operations.  
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3 Functional Description  
Write Operations  
Figure 3-1 provides a high-level overview of the tape drives flow of  
data during a write operation.  
1
3
Data not to be compressed  
Data written to tape  
4
SCSI  
bus  
Data  
buffer  
Ta p e  
2
Read-after-write  
Data to be  
compressed  
5
Compression  
circuit  
Rewrite (if necessary)  
Figure 3-1 Data flow during a write operation  
Data Flow and Data Compression  
The data-flow process during a write operation is outlined below.  
(The steps below correspond to the circled numbers in Figure 3-1.)  
These steps are described in further detail in the rest of this section.  
¬
If you select uncompressed format (8200 or 8500) for the tape,  
the data goes directly from the SCSI bus to the tape drives  
1-MByte DRAM data buffer. (Data transfers between the SCSI  
bus and the buffer occur asynchronously or synchronously.)  
-
If you select compressed format (8200c or 8500c) for the tape, the  
tape drive looks at the currently active MODE SELECT  
parameters to see if data compression has been turned on.  
Note: If you select 8200c format, data compression is always on;  
you cannot turn it off.  
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3 Functional Description  
If data compression is turned on, the data goes from the SCSI  
bus to the compression integrated circuit where it is compressed  
and then decompressed. The tape drive performs a Compression  
Integrity Check™ by comparing the decompressed data to the  
original data.  
If the decompressed data does not match the original data, the  
tape drive indicates that a compression error has occurred and  
does not write the data to tape.  
If the decompressed data matches the original data or if data  
compression was turned off, the tape drive appends two bytes  
of CRC data to each logical block. Then, it transfers the data to  
its data buffer.  
Note: The tape drive compresses data written to tape at an  
average ratio of 2:1. However, the actual compression  
ratio achieved depends on the type of data to be  
compressed.  
®
Once the motion threshold is exceeded in the data buffer, tape  
motion begins, ECC and physical-block CRC bytes are  
integrated with each physical block, and data is written to tape.  
¯
°
The tape drive performs a read-after-write check on the written  
data to ensure that the data on tape was written accurately.  
If necessary, the tape drive rewrites the data.  
Logical Block CRC  
The tape drive adds two bytes of cyclic redundancy check (CRC) data  
to every logical block written in compressed format. These bytes add  
an extra check to ensure that the user data is compressed and  
decompressed accurately.  
Note: These logical block CRC bytes are in addition to the two bytes  
of physical block CRC data that the tape drive adds to every  
physical block on tape.  
Adding logical block CRC bytes to each logical block reduces the data  
capacity of the tape by two bytes for every logical block. For example,  
if you are writing 1,024-byte logical blocks, the data capacity of the  
tape will be reduced by 0.2% (that is, 2 ÷ 1,024 × 100%).  
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3 Functional Description  
Data Compression Monitoring  
The tape drive constantly monitors the compression ratio to  
determine whether compressing the data will actually decrease the  
size of the data set. When a logical block expands (as it might, for  
example, when it has already been compressed by the initiator), the  
tape drive automatically switches to uncompressed format. It remains  
in this format until it encounters a compressible logical block. Then, it  
switches back to the compressed format.  
Streaming and Start/Stop Modes  
The data buffer enables the tape drive to operate as either a streaming  
tape device or as a start/ stop tape device. When the tape drive  
transfers data to the 1-MByte data buffer, the data buffers formatter  
performs the following tasks:  
Formats logical user data blocks into physical blocks  
Appends tag, address, and index information to each data block  
The mode of operation (streaming or start/ stop) depends on the rate  
that data can be transferred between the initiator and the tape drive,  
as follows:  
The tape drive operates in streaming mode if the initiator can  
sustain a minimum of:  
1 MByte per second for 8500c format (EXB-8505 and  
EXB-8505XL only)  
500 Bytes per second for 8500 format (EXB-8505 and  
EXB-8505XL only)  
500 KBytes per second for 8200c format  
262.5 KBytes per second for 8200 format  
Note: These values assume a 2:1 compression ratio for 8500c and  
8200c formats.  
The tape drive operates in start/stop mode if the initiator cannot  
sustain these minimum transfer rates; starting and stopping occur  
automatically.  
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3 Functional Description  
Thresholds During a Write Operation  
In start/ stop mode, the motion threshold controls the starting and  
stopping of tape motion. In streaming mode, the reconnect threshold  
controls the rate of disconnects and reconnects between the tape drive  
and the initiator. The values of both of these thresholds can be  
changed with a MODE SELECT command.  
Motion Threshold  
In a start/ stop write operation, the initiator-to-buffer transfer speed is  
slower than the buffer-to-tape transfer speed. In this mode of  
operation, the motion threshold value represents the minimum  
amount of data that must be in the tape drives 1-MByte DRAM data  
buffer before tape motion will start. When the initiator sends data to  
the tape drive, the tape drive waits until the buffer reaches the motion  
threshold to begin writing. Then it writes data to tape until the buffer  
is empty.  
The buffer allows the tape drive to operate with fewer starts and  
stops, reducing wear on the tape and the tape drive.  
Reconnect Threshold  
In a streaming write operation, the initiator-to-buffer transfer rate is  
equal to or greater than the buffer-to-tape transfer rate. In this mode  
of operation, the tape drive writes data to tape continually. When the  
buffer becomes full, the tape drive disconnects from the initiator, and  
the initiator is free to perform other tasks.  
For the tape drive to continue streaming, the initiator must begin  
sending data again before the buffer is empty. The reconnect  
threshold value represents the minimum amount of free space that  
must be in the tape drives 1-MByte buffer before the tape drive will  
reconnect to the initiator to accept additional data. When the  
reconnect threshold value is exceeded, the tape drive reconnects to  
the initiator and data transfer resumes until the buffer is full.  
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3 Functional Description  
Error Detection, Correction, and Recovery Procedures  
As the tape drive writes data to tape, it integrates error correction  
code (ECC) and physical-block cyclic redundancy check (CRC) bytes  
with each physical block. After it writes data, the tape drive uses the  
ECC and CRC to perform a read-after-write check to ensure data  
reliability. By using read-after-write error checking and sophisticated  
error correction procedures, the tape drive offers a non-recoverable  
17  
error rate of less than one bit in 10 bits read.  
Error Correction Code (ECC)  
The Reed/ Solomon ECC algorithms can correct a burst as long as 264  
consecutive bytes in error and as many as 80 additional random  
errors in each physical data block. The ECC is capable of multiple  
burst and random error corrections. It has been designed to be  
extremely effective against the types of error patterns that may occur  
in cartridge tape subsystems that use helical-scan technology.  
Cyclic Redundancy Check (CRC)  
The tape drive also adds two bytes of CRC data to every physical  
block on tape. The CRC data is used in the read-after-write check.  
Read-After-Write Checking  
The tape drive performs a read-after-write check of the recorded user  
data to ensure full data reliability. If the tape drive determines that  
any data blocks should be rewritten, it rewrites the data without  
requiring host intervention or repositioning of the tape.  
For more information about how the tape drive corrects data during  
the read-after-write check, refer to Chapter 6.  
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3 Functional Description  
Read Operations  
Figure 3-2 provides a high-level overview of the tape drives flow of  
data during a read operation.  
1
Uncompressed data  
Data read from tape  
SCSI  
bus  
Data  
buffer  
Ta p e  
2
Data to be  
decompressed  
Decompression  
circuit  
Figure 3-2 Data flow during a read operation  
The process for reading logical blocks of user data is outlined below.  
¬
The tape drive reads data from tape, uses ECC to correct errors  
as necessary for each physical block, and transfers data to the  
data buffer. The read operation continues until the buffer is full  
and tape motion stops.  
-
If the data has not been compressed, the data goes directly from  
the data buffer to the SCSI bus.  
If the data has been compressed, the data goes from the data  
buffer to the decompression circuit to be decompressed. Then,  
the decompressed data is sent to the SCSI bus.  
In either case, the 2-byte logical block CRC, which was  
appended when the data was written, is again verified. This  
final integrity check assures that all block reconstruction and  
decompression was successful.  
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3 Functional Description  
Thresholds During a Read Operation  
The motion threshold controls the starting and stopping of tape  
motion. The reconnect threshold controls the rate of disconnects and  
reconnects between the tape drive and the initiator.  
Motion Threshold  
In a start/ stop read operation, the tape-to-buffer transfer speed is  
faster than the buffer-to-initiator transfer speed. In this mode of  
operation, the motion threshold value represents the minimum  
amount of free space that must be in the tape drives 1-MByte buffer  
before tape motion will start and data will be read from the tape to  
the buffer. The read-from-tape operation continues until the buffer is  
full and tape motion stops. Tape motion does not restart until the  
amount of free space in the buffer once again exceeds the motion  
threshold value.  
Reconnect Threshold  
In a streaming read operation, the tape-to-buffer transfer rate is equal  
to or less than the buffer-to-initiator transfer rate. In this mode of  
operation, the tape drive reads data from tape continually. When the  
buffer becomes empty, the tape drive disconnects from the initiator,  
and the initiator is free to perform other tasks.  
For the tape drive to continue streaming, the initiator must begin to  
accept data again before the buffer is full. The reconnect threshold  
value represents the minimum amount of data that must be in the  
tape drives 1-MByte buffer before the tape drive will reconnect to the  
initiator to transfer data from the buffer. When the reconnect  
threshold value is exceeded, the tape drive reconnects to the initiator  
and data transfer resumes. The data transfer to the initiator continues  
until the buffer is empty.  
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4
Requirements for Use  
This chapter specifies the requirements for installing, operating,  
maintaining, and shipping the EXB-8205, EXB-8205XL, EXB-8505, and  
EXB-8505XL. This chapter includes the following sections:  
Installation requirements  
Operation  
Preventive maintenance  
Loading new microcode  
Shipping requirements  
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4 Requirements for Use  
Installation Requirements  
Installing the tape drive involves the following steps:  
Setting the SCSI ID  
Mounting the tape drive in a mounting frame (if desired)  
Terminating the tape drive (if necessary)  
Connecting a SCSI cable to the tape drive  
Connecting the tape drive to the power supply  
This section describes the requirements for installing the tape drive.  
For step-by-step instructions for completing installation tasks, refer to  
EXB-8205 and EXB-8505 Installation and Operation.  
Requirements for Setting the SCSI ID  
The SCSI ID is the address asserted by the tape drive during  
arbitration. The SCSI ID is set at the factory; if you want to change the  
tape drives SCSI ID (0 through 7), you can do one of the following:  
Remove and reposition the jumpers on the SCSI ID jumper block  
on the back of the tape drive (see Figure 4-1).  
Remove the jumpers and connect a remote switch to the SCSI ID  
jumper block. A remote switch is not provided with the tape  
®
drive. Use a female Molex 22-55-2061 or equivalent cable  
connector to control the address remotely.  
Figure 4-1 SCSI ID jumper block on the back panel (single-ended configuration)  
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4 Requirements for Use  
Note that changes in the SCSI ID setting will not take effect until one  
of the following conditions occur:  
Normal power-on  
The tape drive is reset by a SCSI bus reset  
The tape drive receives a Bus Device Reset message  
For detailed instructions for setting the SCSI ID, including the pin  
assignments for the SCSI ID jumper block, refer to EXB-8205 and  
EXB-8505 Installation and Operation.  
Requirements for Mounting the Tape Drive  
The main housing of the tape drive includes three sets of mounting  
holes (two sets on the sides and one set on the bottom) to allow for a  
number of mounting positions. The tape drive can be mounted either  
horizontally or vertically and in a stationary or sliding position.  
When mounting the tape drive, follow these guidelines:  
Use either one of the two sets of four mounting holes on the sides  
of the tape drive (shown as “A” or “B” in Figure 4-2) or the four  
mounting holes on the bottom of the tape drive (shown as “C” in  
Figure 4-3).  
Use all four holes in whichever set you choose. Do not use  
combinations of mounting holes from different sets.  
Ensure that the tape drive is securely mounted and that the  
chassis is not subject to distortion.  
Ensure that no objects such as screw heads, cables, or adjacent  
devices are pressing against the frame.  
Do not obstruct the ventilation slots of the device. This ensures  
that the tape drive can be adequately cooled.  
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4 Requirements for Use  
Figure 4-2 Mounting holes on the sides  
Figure 4-3 Mounting holes on the bottom  
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4 Requirements for Use  
The mounting holes accommodate M3 × 0.5 × 6 mm screws and are  
designed for standard 5.25-inch half-high form factor mounting  
requirements. The holes are 0.31 inches (7.9 mm) deep.  
Figure 4-4 shows the dimensions for the tape drives mounting holes.  
Figure 4-4 Mounting hole dimensions in inches (and millimeters)  
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4 Requirements for Use  
Requirements for SCSI Bus Termination  
If the tape drive is the last device on the SCSI bus, it must be  
terminated. As described in this section, the termination requirements  
for the tape drive depend on whether it uses a single-ended or  
differential SCSI configuration.  
Terminators for Single-Ended Configuration  
The single-ended SCSI configuration includes three single in-line  
package (SIP) resistor terminators (R-packs). They can be left in place  
if the tape drive terminates the SCSI bus or removed if the tape drive  
does not terminate the SCSI bus or if external termination is used.  
If necessary, the single-ended tape drive can be terminated externally.  
To ensure that the tape drive performs to specification, Exabyte  
®
recommends a Methode Electronics, Inc. dataMate DM103-02-0  
single-ended external terminator.  
Terminators for Differential Configuration  
The differential SCSI configuration of the tape drive does not include  
internal terminators. If a differential tape drive terminates the SCSI  
bus, it must be terminated externally. To ensure that the tape drive  
performs to specification, Exabyte recommends a Methode  
Electronics, Inc. dataMate DM103-01-0 differential external terminator.  
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4 Requirements for Use  
Requirements for Connecting a SCSI Cable  
The cable for connecting the tape drive to the SCSI bus is not  
provided with the tape drive. You must provide a cable that complies  
with the appropriate safety and regulatory agency requirements. To  
comply with FCC, Canadian DOC, and VDE limits, the tape drive  
requires shielded cables when the cables are external to the mounting  
enclosure.  
Impedance  
Ideally, to match the cable terminators, the cable should have a  
characteristic impedance of 122 ohms (differential) or 132 ohms  
(single-ended). However, since cables with this high of a characteristic  
impedance are not generally available, somewhat lower impedances  
are acceptable. A characteristic impedance of 100 ohms ± 10% is  
recommended for unshielded flat or twisted-pair ribbon cable. A  
characteristic impedance greater than 90 ohms is recommended for  
shielded cables.  
Important To minimize discontinuities and signal reflections,  
Exabyte recommends that cables used on the same bus have the  
same impedances.  
#
Cable Length  
The maximum length of the SCSI cable depends on whether you are  
using a single-ended or differential SCSI configuration, as follows:  
For single-ended SCSI configurations, the maximum allowable  
bus length is 6 meters (19.7 feet). A stub length of no more than  
0.1 meters (4 inches) is allowed off the mainline interconnection  
within any connected equipment.  
For differential SCSI configurations, the maximum allowable bus  
length is 25 meters (82 feet). A stub length of no more than  
0.2 meters (8 inches) is allowed off the mainline interconnection  
within any connected equipment.  
May 1994  
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4-7  
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4 Requirements for Use  
Primary Conductor  
A minimum primary conductor size of 28 AWG is recommended to  
minimize noise effects and ensure proper distribution of terminator  
power.  
SCSI Cable Connector Requirements  
The SCSI connector is located at the back of the tape drive, as shown  
in Figure 4-5. The connector is a 50-pin male ribbon cable connector.  
The stub length within the tape drive is less than 50 mm.  
Figure 4-5 SCSI connector location on the back panel  
To connect the tape drive to the SCSI bus, use a 50-pin female ribbon  
cable connector (AMP No. 1-746285-0 or equivalent).  
Table 4-1 shows the connector pin assignments for differential tape  
drives; Table 4-2 shows the connector pin assignments for  
single-ended tape drives.  
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4 Requirements for Use  
Table 4-1 Connector pin assignments for differential tape drives  
Signal  
Pin Number  
Signal  
SHIELD GROUND  
+DB(0)  
+DB(1)  
+DB(2)  
+DB(3)  
+DB(4)  
+DB(5)  
+DB(6)  
+DB(7)  
+DB(P)  
DIFFSENS  
GROUND  
TERMPWR  
GROUND  
+ATN  
1
2
GROUND  
–DB(0)  
–DB(1)  
–DB(2)  
–DB(3)  
–DB(4)  
–DB(5)  
–DB(6)  
–DB(7)  
–DB(P)  
GROUND  
GROUND  
TERMPWR  
GROUND  
–ATN  
3
4
5
6
7
8
9
10  
12  
14  
16  
18  
20  
22  
24  
26  
28  
30  
32  
34  
36  
38  
40  
42  
44  
46  
48  
50  
11  
13  
15  
17  
19  
21  
23  
25  
27  
29  
31  
33  
35  
37  
39  
41  
43  
45  
47  
49  
GROUND  
+BSY  
GROUND  
–BSY  
+ACK  
–ACK  
+RST  
–RST  
+MSG  
–MSG  
+SEL  
–SEL  
+C/D  
–C/D  
+REQ  
–REQ  
+I/O  
–I/O  
GROUND  
GROUND  
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4 Requirements for Use  
Table 4-2 Connector pin assignments for single-ended tape drives  
Signal  
Pin Number*  
+DB(0)  
+DB(1)  
+DB(2)  
+DB(3)  
+DB(4)  
+DB(5)  
+DB(6)  
+DB(7)  
+DB(P)  
GROUND  
GROUND  
GROUND  
2
4
6
8
10  
12  
14  
16  
18  
20  
22  
24  
TERMPWR 26  
GROUND  
GROUND  
–ATN  
28  
30  
32  
34  
36  
38  
40  
42  
44  
46  
48  
50  
GROUND  
–BSY  
–ACK  
–RST  
–MSG  
–SEL  
–C/D  
–REQ  
–I/O  
* All odd pins except pin 25 are connected to ground. Pin 25 is left open.  
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4 Requirements for Use  
Operation  
This section provides general information about operating the tape  
drive. For more detailed instructions, refer to EXB-8205 and EXB-8505  
Installation and Operation.  
Power-On Mode  
In its normal power-on mode, the tape drive completes a power-on  
self-test in approximately 30 seconds. Once the power-on self test is  
complete, the tape drive loads the tape (if already inserted), and  
positions the tape at LBOT.  
Tape Drive Controls  
The only operator control on the tape drive is the unload button on  
the front panel. Pushing this button starts the unload procedure. This  
button can also be used to reset the tape drive if a servo error occurs.  
The EXB-8205 and EXB-8505 have a smooth unload button. The  
EXB-8205XL and EXB-8505XL have a diamond-textured unload  
button.  
Device States  
Figure 4-6 shows the orientation of the green, amber, and dual  
green/ amber LEDs on the front panel of the EXB-8505 and  
EXB-8505XL. Figure 4-7 shows the orientation of the LEDs on the  
front panel of the EXB-8205 and EXB-8205XL. The three LEDs are  
status indicators.  
May 1994  
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4 Requirements for Use  
Figure 4-6 LEDs on the faceplate of the EXB-8505 and EXB-8505XL  
Figure 4-7 LEDs on the faceplate of the EXB-8205 and EXB-8205XL  
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4 Requirements for Use  
Different LED combinations indicate the tape drives operating state,  
as follows:  
When the top (amber) LED is on or flashing, the tape drive either  
has an error or needs to be cleaned.  
When the middle LED is on or flashing, SCSI bus activity is  
occurring. The middle LED can be green or amber, as follows:  
When this LED is amber, the tape loaded in the tape drive is  
in compressed format (8500c or 8200c).  
When this LED is green, the tape loaded in the tape drive is in  
uncompressed format (8500 or 8200).  
When the bottom (green) LED is on or flashing, tape motion is  
occurring.  
Table 4-3 shows the various combinations of LEDs that may occur to  
indicate different operating states during tape drive operation.  
Table 4-3 LED states during operation  
Tape Drive State  
POST  
(1st  
part)  
POST  
Failed Ready– Ready– Normal High-  
SCSI  
bus  
reset  
Error  
Time to Cleaning  
(to com- POST no tape  
pletion)  
tape  
tape  
speed  
tape  
clean  
tape  
loaded loaded motion  
loaded  
motion  
Top  
LED  
fast  
slow  
fast  
(errors)  
Middle  
LED  
(green) irregular irregular irregular irregular irregular irregular irregular irregular irregular irregular  
(SCSI)a  
b
Bottom  
LED  
slow  
fast  
fast  
slow  
(motion)  
a Green–EXB-8500 or EXB-8200 uncompressed format tape.  
Amber–EXB-8500c or EXB-8200c compressed format tape.  
b
If a tape is loaded, the bottom LED will flash slow and then fast during the second part of the power-on self-test.  
Key for Table 4-3  
The LED is on.  
The LED is off.  
The LED is flashing:  
slow = 1 flash/second (0.94 Hz)  
fast = 4 flashes/second (3.76 Hz)  
irregular = Rate of flash varies with SCSI bus activity. If the tape drive  
is not connected to the bus, the LED will be off.  
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4-13  
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4 Requirements for Use  
Note: Table 4-3 documents the LED combinations that you are likely  
to observe during normal tape drive operation. You may  
occasionally observe other LED combinations and sequences.  
These other combinations represent special or unusual  
conditions that are beyond the scope of this table. (For  
example, a fairly complex LED sequence occurs when you  
load new microcode from tape.)  
Loading Data Cartridges  
To load a tape into the tape drive, first set the write-protect switch on  
the EXATAPE data cartridge as required (either write protected or  
write enabled), then insert the data cartridge into the tape drive.  
Make sure you are using a data cartridge that is compatible with your  
tape drive. For information on tape drive and media compatibility,  
see Chapter 1.  
Important EXATAPE 160m XL media is compatible with the  
#
EXB-8205XL and EXB-8505XL only. The EXB-8205 and EXB-8505  
will automatically eject these data cartridges. Do not use 160m XL  
data cartridges in Exabyte full-high tape drives.  
When you insert a cartridge, the tape drive automatically loads the  
cartridge, unless the initiator has issued a MODE SELECT (15h)  
command to disable the autoload function. Once the data cartridge is  
loaded, the tape drive presents ready status (bottom green LED on)  
and commands requiring loaded media will execute normally.  
Notes:  
If you disabled the autoload function, the tape drive does  
not present ready status until the initiator issues a LOAD  
(1Bh) command.  
If you attempt to load a cartridge during a power-on  
self-test, the tape drive will eject the cartridge.  
If you attempt to load a 160m data cartridge that is not  
equipped with an Exabyte Recognition System stripe into  
an EXB-8205XL or EXB-8505XL, the tape drive will eject the  
cartridge.  
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4 Requirements for Use  
Refer to EXB-8205 and EXB-8505 Installation and Operation for  
instructions for setting the write-protect switch and loading data  
cartridges in the tape drive. Refer to the EXB-8205 and EXB-8505 SCSI  
Reference for information about the MODE SELECT and LOAD  
commands.  
Load Time  
The time required to load the data cartridge and position the tape to  
LBOT after the data cartridge is inserted is approximately 60 seconds.  
When loading a tape, the tape drive spaces forward from PBOT and  
determines the following:  
The tape format. The format will be either 8200, 8200c, 8500,  
8500c, or unknown.  
The adaptive servo parameters. This process enables the tape  
drive to read tapes produced by different manufacturers, tapes  
that are aged and worn, and tapes written by other 8mm tape  
drives.  
The length of the tape in use. The tape drive autosizes the data  
cartridge to determine the tape length. For more information  
about autosizing, refer to the EXB-8205 and EXB-8505 SCSI  
Reference.  
Unloading Data Cartridges  
You can unload a data cartridge by either pressing the unload button  
or by issuing an UNLOAD (1Bh) command. This section describes  
what happens when the unload button is pressed. For information  
about using the LOAD/ UNLOAD (1Bh) command, see the EXB-8205  
and EXB-8505 SCSI Reference.  
If a data cartridge is loaded and the tape drive is error free, the tape  
drive performs the following actions when you press the unload  
button:  
Completes any command that is currently in progress  
Writes any buffered information to tape  
Writes EOD (except in 8200 format)  
Rewinds the tape to physical beginning of tape (PBOT)  
Unloads the tape from the tape path and ejects the tape  
In addition, the tape drive has several unload button options for  
“normal,” “fast,” and “super fast” unload operations.  
May 1994  
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4 Requirements for Use  
Effect of PREVENT/ALLOW MEDIUM REMOVAL Command  
If an initiator has issued a PREVENT MEDIUM REMOVAL (1Eh)  
command to prevent the removal of the data cartridge, the tape drive  
will not eject the data cartridge until the initiator sends an ALLOW  
MEDIUM REMOVAL (1Eh) command to allow you to remove the  
data cartridge.  
For more information about using the PREVENT/ ALLOW MEDIUM  
REMOVAL command, see the EXB-8205 and EXB-8505 SCSI Reference.  
Error During Unload Procedure  
If an error exists before or during the unload procedure, the tape  
drive suspends the preceding sequence of events and the top amber  
LED will flash. If you press the unload button again, the tape drive  
reattempts the unload sequence; however, the tape drive does not  
write data in the buffer to tape. The tape drive clears the buffer and  
errors.  
Resetting the Tape Drive  
You can reset the tape drive by any of the following methods:  
Powering the tape drive off and back on again (power-on reset).  
Sending an RST pulse on the SCSI bus for a minimum of 25 µsec  
(SCSI bus or “hard” reset). A SCSI bus reset immediately clears all  
devices from the bus and resets their associated equipment.  
Issuing a Bus Device Reset (0Ch) message to the tape drive  
(device or message reset). A device reset clears the tape drive  
from the bus and causes all commands to be cleared.  
Pressing the unload button to clear a servo error.  
Note: If a SCSI bus or device reset occurs during a power-on reset,  
the tape drive will perform a full power-on reset.  
If the tape drive has a data cartridge inserted or loaded when a reset  
condition occurs, it rewinds the tape and positions to LBOT after the  
reset operation is complete. The total time required for the reset may  
be as long as three minutes if the tape is positioned near the end of  
tape.  
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4 Requirements for Use  
Using SCSI Commands  
You can use SCSI commands to read, write, erase, and search for data.  
You can also copy microcode, inquire about tape drive status, set  
operating parameters, and perform diagnostic tests using SCSI  
commands.  
For information on these commands and how to use them, see  
Preventive Maintenance  
Except for cleaning, the tape drive has no user serviceable  
adjustments or maintenance procedures. All service or repairs to the  
tape drive must be performed by Exabyte Corporation or authorized  
service personnel.  
Cleaning the Tape Drive  
The tape drives tape heads and tape path should be cleaned on a  
regular basis. The only cleaning material authorized for use with the  
tape drive is an Exabyte or Exabyte-approved 8mm cleaning cartridge.  
CAUTION  
To prevent contamination of the tape drive and damage to the  
heads, do not attempt to rewind the material in the cleaning  
cartridge and reuse it. Discard the cleaning cartridge after you have  
used it for the specified number of cleaning cycles.  
Using any cleaning cartridges not approved by Exabyte will void  
the warranty on the tape drive.  
For more information on Exabyte cleaning cartridges, see Chapter 1.  
For instructions for using the cleaning cartridge, refer to EXB-8205  
and EXB-8505 Installation and Operation.  
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4 Requirements for Use  
Determining When the Tape Drive Needs Cleaning  
You should clean the tape drives heads and tape path after every 30  
tape motion hours. This cleaning frequency does not depend on the  
format in which you write and read data. However, if you are using  
the tape drive in a particularly dirty environment or if you operate it  
infrequently, you may want to clean it more often than every 30 tape  
motion hours. Cleaning the tape drive helps to ensure that it will  
perform according to its specifications.  
Time-to-Clean LED Indication  
The tape drive keeps track of tape motion hours internally. When 30  
tape motion hours have elapsed, the top and bottom LEDs will flash  
rapidly and the middle LED will flash irregularly, depending on SCSI  
bus activity (see Table 4-3). For best results, clean the tape drive as  
soon as possible after the LEDs begin flashing.  
REQUEST SENSE (03h) Command  
If desired, you can issue a REQUEST SENSE (03h) command and look  
at the setting of the CLN and CLND bits (byte 21, bits 4 and 3). If the  
CLN bit is set to 1, the tape drive needs to be cleaned. This bit is reset  
to 0 when a successful cleaning cycle has been performed. The CLND  
bit is set to 1 when the tape drive has been cleaned and is reset to 0  
when the next REQUEST SENSE command is received.  
Loading New Microcode  
To upgrade the microcode in the tape drive, you can:  
Use a microcode update tape that you obtain from Exabyte (no  
special software required)  
Create a microcode update tape from another tape drive using the  
Exabyte CTS Monitor program  
Use Exabyte microcode update diskettes with CTS Monitor  
Copy microcode from the Exabyte Technical Support bulletin  
board and load it in your tape drive using CTS Monitor  
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4 Requirements for Use  
Use the READ BUFFER command to copy the new code from a  
tape drive across the SCSI bus to an initiator. You can then use the  
WRITE BUFFER command to copy the code from the initiator to  
another tape drive.  
For more information about the CTS Monitor program, refer to the  
CTS Monitor documentation. For more information about using SCSI  
commands, refer to the EXB-8205 and EXB-8505 SCSI Reference.  
Shipping Requirements  
This section describes the shipping requirements for the tape drive,  
including information about the shipping carton and a list of the  
environmental conditions needed for transporting the tape drive.  
Shipping Cartons  
The tape drive is sealed in a static protection bag and is shipped with  
either one drive per carton (single pack) or with three to five drives  
per carton (multi-pack).  
Table 4-4 shows shipping dimensions and weights for the tape drive.  
Table 4-4 Single pack and multi-pack shipping dimensions and weights  
Size  
Dimensions  
Weight  
Single-pack  
1 CTS: 4.5 lbs (2.0 kg)  
13.5 inches long ×  
10.75 inches wide ×  
8.5 inches high  
(34.3 × 27.3 × 21.6 cm)  
Multi-pack  
3 CTSs: 12 lbs (5.4 kg)  
4 CTSs: 15 lbs (6.5 kg)  
5 CTSs: 18 lbs (8.2 kg)  
23.25 inches long ×  
13.5 inches wide ×  
11.5 inches high  
(59.1 × 34.3 × 29.2 cm)  
May 1994  
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4 Requirements for Use  
Both the single-pack and the multi-pack shipping cartons and internal  
packing materials are designed so that an enclosed tape drive does  
not receive a shock greater than 45 g when the carton is dropped on  
any surface, corner, or edge from the following heights:  
48 inches (121.9 cm) at a velocity change of 192 inches per second  
(488 cm/ sec) for the single-pack carton  
36 inches (91.4 cm) at a velocity change of 167 inches per second  
(424 cm/ sec) for the multi-pack carton  
Both sizes of shipping carton pass the tests described in the National  
Safe Transit Association (NSTA) Project 1A for packaged products  
weighing less than 100 pounds.  
Note: Do not use a multi-pack shipping carton when shipping a  
single tape drive. If you use a multi-pack shipping carton, you  
must place three, four, or five tape drives in the carton.  
The packing materials are unbleached, reusable, recyclable, and  
environmentally safe. The materials contain no chlorofluorocarbons  
(CFCs) or heavy metals.  
Unpacking and Packing Instructions  
Unpacking and packing instructions for the tape drive are included in  
EXB-8205 and EXB-8505 8mm Cartridge Tape Subsystem Installation and  
Operation.  
To avoid damaging the tape drive, use the original shipping carton  
and packing materials (or replacement packaging obtained from the  
vendor) when repacking and shipping the tape drives. The shipping  
carton and packing materials are not intended to be used for shipping  
items other than an Exabyte half-high tape drive.  
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5
Interface Specifications  
This chapter describes the tape drives SCSI interface, including the  
following sections:  
SCSI features  
Physical path  
SCSI messages  
SCSI commands  
Using SCSI commands  
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5 Interface Specifications  
SCSI Features  
Implementation characteristics of the Small Computer System  
Interface (SCSI) controller include the following:  
Support for single-ended or differential SCSI configurations.  
SCSI bus parity checking configurable through the MODE  
SELECT command.  
Support for multiple initiator configurations.  
Support of the disconnect, reconnect, and arbitration feature,  
which releases the tape drive from the bus so that it can operate  
under its own internal intelligence system, enabling the SCSI bus  
to perform other I/ O requests.  
The SCSI implemented for the tape drive conforms to the following  
standard for a sequential access device: ANSI Small Computer System  
Interface-2 (SCSI-2), X3.131-1994.  
Data Transfer Rate  
The maximum obtainable data transfer rates for the tape drive  
depend on what mode it is operating in. For information on data  
transfer rates, see Chapter 6.  
Physical Path  
The physical path implemented by the tape drive includes an  
eight-port, daisy-chained bus with the following features:  
Single-host or multiple-host computer system capability  
Bus contention handled by distributed arbitration on a prioritized  
basis  
Accommodation of multiple peripheral device types  
Multiple overlap of peripheral device operations  
Orientation toward intelligent peripheral devices  
Enhanced operation with buffered devices  
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5 Interface Specifications  
SCSI Messages  
The SCSI message system supported by the tape drive allows  
communication between the initiator and the tape drive for physical  
path management. Table 5-1 lists the SCSI messages supported by the  
EXB-8205, EXB-8205XL, EXB-8505, and EXB-8505XL.  
Refer to the EXB-8205 and EXB-8505 SCSI Reference for detailed  
information about SCSI communications and messages.  
Table 5-1 SCSI messages  
In  
Out  
Hex Value  
Description  
(Tape drive to (Initiator to  
initiator)  
tape drive)  
4
00h  
01h  
Command Complete  
Extended Message  
(Synchronous Data  
Transfer Request)  
4
4
4
4
4
02h  
Save Data Pointers  
Restore Pointers  
Disconnect  
03h  
04h  
4
4
4
4
4
4
4
05h  
Initiator Detected Error  
Abort  
06h  
4
07h  
Message Reject  
No Operation  
08h  
09h  
Message Parity Error  
Bus Device Reset  
Identify  
0Ch  
80h or C0h  
4
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5 Interface Specifications  
SCSI Commands  
The SCSI-2 command set supported by the tape drive consists of 19  
six-byte commands (Group 0 command set) and 6 ten-byte  
commands (Group 1 command set). These commands are listed in  
Note: Tapes written and read in 8200 format use the SCSI-1  
command set. See the EXB-8205 and EXB-8505 SCSI Reference  
for more information.  
Table 5-2 SCSI-2 command set  
Description  
Command  
OP Code  
ERASE  
19h  
Causes the tape drive to erase all tape from the  
current tape position to the physical end of tape.  
INQUIRY  
12h  
1Bh  
2Bh  
Requests that information about the tape drive  
parameters be sent to the initiator.  
LOAD/UNLOAD  
LOCATE  
Causes the tape drive to load or unload the data  
cartridge.  
Allows you to position the tape at a specified logical  
block address. Used in conjunction with the READ  
POSITION command.  
LOG SELECT  
4Ch  
Allows you to manage the counters that the tape drive  
maintains about its write and read error recovery  
operations.  
LOG SENSE  
4Dh  
15h  
1Ah  
1Eh  
08h  
05h  
Allows you to retrieve statistical information about the  
tape drive’s read and write error recovery operations.  
MODE SELECT  
MODE SENSE  
Allows you to specify medium, logical unit, and device  
parameters.  
Enables the tape drive to report medium, logical unit,  
or device parameters.  
PREVENT/ALLOW MEDIUM  
REMOVAL  
Allows or disallows the removal of the data cartridge  
from the tape drive.  
READ  
Transfers one or more bytes or blocks of data from the  
tape to the initiator.  
READ BLOCK LIMITS  
Requests that the tape drive return data identifying the  
maximum and minimum logical block lengths  
supported.  
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5 Interface Specifications  
Description  
Command  
OP Code  
READ BUFFER  
3Ch  
Copies the tape drive’s microcode across the SCSI  
bus to the initiator. Used in conjunction with the  
WRITE BUFFER command.  
READ POSITION  
34h  
1Ch  
Reports the tape drive’s current logical position but  
does not cause tape motion to occur. Used in  
conjunction with the LOCATE command.  
RECEIVE DIAGNOSTIC  
RESULTS  
Reports the results of the tests requested by a  
previous SEND DIAGNOSTIC command or to obtain a  
trace of SCSI and servo command activity for the tape  
drive.  
RELEASE UNIT  
17h  
Releases a tape drive from an initiator’s exclusive use,  
or if third-party reservations are in effect, from another  
SCSI device’s use. Used in conjunction with the  
RESERVE UNIT command.  
REQUEST SENSE  
RESERVE UNIT  
03h  
16h  
Requests that the tape drive transfer sense data to the  
initiator.  
Reserves the tape drive for an initiator’s exclusive use,  
or if third-party reservations are in effect, for another  
SCSI device’s use. Used in conjunction with the  
RELEASE UNIT command.  
REWIND  
01h  
1Dh  
11h  
00h  
13h  
0Ah  
3Bh  
Causes the tape drive to rewind the tape to the logical  
beginning of tape.  
SEND DIAGNOSTICS  
SPACE  
Causes the tape drive to perform certain  
self-diagnostic tests.  
Enables the tape drive to perform forward or backward  
searches.  
TEST UNIT READY  
VERIFY  
Allows you to determine if the tape drive is ready to  
accept an appropriate medium access command.  
Enables the tape drive to verify one or more logical  
blocks of data on the tape.  
WRITE  
Transfers one or more bytes or blocks of data from the  
initiator to the tape drive.  
WRITE BUFFER  
Allows you to load new microcode from the SCSI bus  
into the tape drive’s control memories. Used in  
conjunction with the READ BUFFER command.  
WRITE FILEMARKS  
10h  
Causes the tape drive to write zero, one, or more  
filemarks or setmarks (8500c format) to tape.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
5-5  
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5 Interface Specifications  
Using SCSI Commands  
This section describes the SCSI commands used to write, read, erase,  
and search for data, and to copy microcode, inquire about tape drive  
status, set operating parameters, and perform diagnostic tests.  
Writing Data  
To transfer bytes or blocks of data from the initiator to the tape drive,  
use the WRITE (0Ah) command. The data can be written in any of the  
four supported logical tape formats (two formats for the EXB-8205  
and EXB-8205XL), which are specified by the MODE SELECT (15h)  
command.  
To write filemarks or setmarks (8500c format only), use the WRITE  
FILEMARKS (10h) command.  
Reading Data  
To transfer bytes or blocks of data from the tape drive to the initiator,  
use the READ (08h) command. The tape drive automatically sets itself  
to the format used when the tape was written and can read tapes that  
have a combination of fixed-length and variable-length blocks.  
Erasing Data  
Use the ERASE (19h) command to erase all tape from the current  
valid tape position to the physical end of tape (PEOT). When the erase  
operation is successfully completed, the tape is automatically  
rewound to the logical beginning of tape (LBOT).  
5-6  
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5 Interface Specifications  
Searching for Data  
To enable the tape drive to perform forward or backward searches,  
use the SPACE (11h) or LOCATE (2Bh) commands. The tape drive  
moves the tape at its high-speed search speed, which is up to 75 times  
the nominal tape speed.  
The tape drive can space over both fixed and variable blocks. The tape  
drive determines the type of spacing to use according to the type of  
block found on the tape.  
Copying Microcode  
Use the READ BUFFER (3Ch) and the WRITE BUFFER (3Bh)  
commands to copy the microcode from one tape drive to another.  
First, issue a READ BUFFER command to place the microcode into  
the correct format and to transfer the microcode image across the  
SCSI bus to the initiator. Next, issue a WRITE BUFFER command to  
transfer the microcode from the initiator to other tape drives.  
Inquiring About Tape Drive Status  
To inquire about tape drive status, you can use the commands  
described below.  
REQUEST SENSE (03h) Command  
Use the REQUEST SENSE (03h) command to determine the type of  
error when an error occurs or to determine tape drive status. For  
errors, this command returns the following information:  
Sense Key for the error that indicates the type of error (such as,  
Not Ready, Hardware Error, Illegal Request, Unit Attention,  
Aborted Command)  
Additional Sense Code (ASC) that indicates the type of error for  
the given sense key  
Additional Sense Code Qualifier (ASCQ) that indicates the  
specific error for the sense key and ASC  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
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5 Interface Specifications  
Fault Symptom Code (FSC) that indicates the specific nature of  
hardware and software errors or other events (the FSC is an  
Exabyte-unique byte)  
INQUIRY (12h) Command  
You can use the INQUIRY (12h) command to obtain information  
about the tape drives firmware level, the version of SCSI supported  
by the tape drive, and so on.  
LOG SENSE (4Dh) and LOG SELECT (4Ch) Commands  
You can use the LOG SENSE (4Dh) command to retrieve the tape  
drives read and write error counters. You can use the LOG SELECT  
(4Ch) command to set threshold values for these counters.  
Performing Diagnostic Tests  
You can perform diagnostics to find out detailed information about  
tape drive operations. The SEND DIAGNOSTIC (1Dh) command  
allows you to run special diagnostic tests, including a drive dump.  
The RECEIVE DIAGNOSTIC RESULTS (1Ch) command allows you  
to obtain diagnostic results or a dump that provides you with  
information about the status of tape drive operations.  
Setting Operating Parameters  
To set operating parameters for the tape drive, use the MODE  
SELECT (15h) command. To find out how the parameters are set for  
the tape drive, use the MODE SENSE (1Ah) command.  
5-8  
EXB-8205 and EXB-8505  
(Standard and XL)  
510504  
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6
Functional  
Specifications  
This chapter includes functional specifications for the tape drive,  
including the following sections:  
Performance specifications  
Reliability specifications  
Power specifications  
Environmental specifications  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-1  
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6 Functional Specifications  
Performance Specifications  
This section describes the performance specifications for the tape  
drive.  
Write and Read Access Times  
Write access time starts when the tape drive receives the last byte of  
the WRITE command (that is, when the initiator de-asserts ACK) and  
ends when the tape drive asserts REQ to request that the initiator  
transfer the first data byte across the SCSI bus.  
Read access time starts when the tape drive receives the last byte of  
the READ command (that is, when the initiator de-asserts ACK) and  
ends when the tape drive asserts REQ to indicate that it is ready to  
transfer the first data byte across the SCSI bus to the initiator.  
Write and read access times depend on whether the tape drive is  
operating in start/ stop mode or streaming mode.  
Table 6-1 Typical write and read access times  
Mode  
Typical write access  
time  
Typical read access  
time  
Start/stop  
Streaming  
1.7 msec  
3.1 msec  
1.8 msec  
3.2 msec  
Note: The measurement of write access time does not include the  
initial WRITE command received after the mode is changed  
from read to write.  
6-2  
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(Standard and XL)  
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6 Functional Specifications  
Tape Speed  
Table 6-2 lists the nominal tape speed at which data can be written  
and read by the tape drives.  
Table 6-2 Nominal tape speed  
Format  
Speed  
EXB-8205 and EXB-8205XL  
EXB-8505 and EXB-8505XL  
8500c  
8500  
11.079 mm/sec (0.436  
inch/sec)  
8200c  
8200  
11.079 mm/sec (0.436 inch/sec)  
11.633 mm/sec (0.458 inch/sec)  
File-Search Tape Speed  
Table 6-3 lists forward and backward file-search tape speeds for the  
tape drives. These high-speed search times occur when the initiator  
issues a LOCATE command (for tapes written in 8200c, 8500, or 8500c  
formats) or a SPACE command (for all formats).  
Table 6-3 File-search tape speeds  
Format  
Forward Speed  
Backward Speed  
EXB-8205 and  
EXB-8205XL  
EXB-8505 and  
EXB-8505XL  
EXB-8205 and  
EXB-8205XL  
EXB-8505 and  
EXB-8505XL  
8500c  
8500  
831 mm/sec max  
(32.7 inch/sec)  
831 mm/sec max  
(32.7 inch/sec)  
8200c  
8200  
831 mm/sec max (32.7 inch/sec)  
116 mm/sec (4.58 inch/sec)  
831 mm/sec max (32.7 inch/sec)  
87.25 mm/sec (3.45 inch/sec)  
8500, 8500c, and 8200c Formats  
If the tape is written in 8500, 8500c, or 8200c formats, the tape drive  
can perform forward and backward file-search operations at up to 75  
times the nominal tape speed.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-3  
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6 Functional Specifications  
8200 Format  
If the tape is written in 8200 format, the tape drive can perform  
forward file-search operations at 10 times the nominal tape speed and  
backward file-search operations at 7.5 times the nominal tape speed.  
Rewind Tape Speed  
Table 6-4 lists maximum rewind times for the tape drives for four  
sizes of EXATAPE 8mm data cartridges. Rewind time starts when the  
initiator issues a REWIND (01h) command and ends when the tape  
drive returns a Command Complete message (for a non-immediate  
rewind). All times listed in the table assume the following:  
The tape is positioned at LEOT when you issue a REWIND  
command.  
The drum has not stopped rotating.  
Tape tension has not been released.  
Table 6-4 Typical rewind times  
Length  
m (ft)  
Typical rewind time  
(seconds)  
Size of  
EXATAPE  
a
15m  
54m  
15 (49)  
54 (177)  
112 (367)  
160 (524)  
50  
100  
170  
240  
112m  
b
160m XL  
a EXATAPE data cartridges are recommended for use with all Exabyte products and  
are available for purchase from Exabyte Corporation.  
b160m XL media is intended for use in the EXB-8205XL and EXB-8505XL only.  
Reposition Time  
Reposition time starts when the initiator issues a command that stops  
the tape drives motion control system and ends when the tape is  
repositioned, at nominal speed, so that the next byte of data can be  
transferred. Reposition time is independent of any interface delays.  
Reposition time for the tape drive ranges from 1.2 sec to 1.5 sec.  
6-4  
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(Standard and XL)  
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6 Functional Specifications  
Drum Rotation Period  
Table 6-5 shows the drum rotation period for the tape drives reading  
and writing tapes in all formats.  
Table 6-5 Drum rotation periods  
Format  
Drum rotation period  
Nominal effective  
head-to-tape speed  
8500c*  
8500*  
8200c  
8200  
32.77 msec  
(1831.055 rpm)  
3.824 m/sec  
(150.548 inch/sec)  
31.21 msec  
4.015 m/sec  
(1922.607 rpm)  
(158.075 inch/sec)  
*EXB-8505 and EXB-8505XL only  
Tape Tension Release and Drum Motion Suspension  
The tape drive releases tape tension under either of the following  
conditions:  
The tape is at LBOT and the tape drive has not received a  
command to move the tape in the last 5 seconds.  
The tape is not at LBOT and the tape drive has not received a  
command to move the tape in the last 15 seconds.  
After releasing tape tension, the tape drive will stop drum rotation if  
it does not receive a tape motion command within the next 60 seconds.  
If tape tension has been released, approximately 1.5 seconds will  
elapse before the tape drive can perform a tape motion command. If  
the drum rotation has been stopped, approximately 7 seconds will  
elapse before the tape drive can perform a tape motion command.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-5  
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6 Functional Specifications  
Data Transfer Rate  
The maximum obtainable data transfer rates for the tape drive  
depend on what mode it is operating in. Table 6-6 shows the data  
transfer rates for each of the four formats.  
Table 6-6 Data transfer rates  
Type of  
transfer  
Rate achieved for these formats . . .  
a
a
8500c  
8500  
8200c  
8200  
Sustained  
transfer rate  
up to 1  
MBytes/sec  
up to 500  
KBytes/sec  
up to 500  
KBytes/sec  
up to 262.5  
KBytes/sec  
b
b
Synchronous  
burst  
up to 5.0 MBytes/sec  
Asynchronous  
burst  
up to 2.5 MBytes/sec  
a EXB-8505 and EXB-8505XL only  
b Assumes a 2:1 compression ratio  
Notes:  
When compression is enabled, the tape drive can increase  
the sustained transfer rate of up to five times. Compression  
throughput and capacity ratios depend on the type of data.  
The maximum burst data transfer rate is limited by the  
performance of the SCSI host bus adapter, the SCSI bus  
interface controller, and the tape drives buffer control  
hardware.  
Reselection Phase Timeout  
If the initiator fails to respond to a device reselection sequence, the  
tape drive times out after 250 msec. The tape drive continues to repeat  
the reselection process until it is reset or the initiator finally responds.  
6-6  
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(Standard and XL)  
510504  
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6 Functional Specifications  
Reliability Specifications  
This section lists the reliability specifications for the tape drive.  
Service Life  
The tape drive has been designed to exceed a useful service life of five  
years, during which time all performance and reliability specifications  
are applicable.  
Machine Reliability: Mean Time Between Failures  
(MTBF)  
The mean time between failures (MTBF) value for the EXB-8205,  
EXB-8205XL, EXB-8505, and EXB-8505XL is 160,000 power-on hours.  
The MTBF value for the tape drive is defined as follows:  
Total Power-on Hours  
MTBF =  
Number of Relevant Equipment Failures  
where:  
Total Power-on Hours is the total time the tape drive is drawing  
current from the input power supply system.  
Relevant Equipment Failures are those failures that cannot be  
corrected by the operating personnel and require the intervention  
of maintenance personnel.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-7  
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6 Functional Specifications  
Test Conditions  
The MTBF value for the tape drive is determined under the following  
conditions:  
MTBF is specified for a maximum duty cycle of 10%, where duty  
cycle is defined as:  
Total Hours of Mechanical Operation  
Total Power-on Hours  
Duty Cycle =  
100%  
The tape drives are tested at the following ambient temperature  
and relative humidity:  
23° C ± 2° C  
50% relative humidity ± 10% (non-condensing)  
The tape drives are operated in accordance with operating  
specifications.  
Conditions for the MTBF Value  
Conditions under which the specifications for MTBF apply are as  
follows:  
The EXATAPE data cartridges used must comply with Standard  
ECMA-145.  
Environmental conditions for the tape drive and the 8mm data  
cartridges must be maintained as specified in the “Environmental  
Specifications” section of this chapter.  
The tape drive must be cleaned with an Exabyte or an  
Exabyte-approved cleaning cartridge using the recommended  
cleaning procedure. Refer to EXB-8205 and EXB-8505 Installation  
and Operation for instructions.  
6-8  
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(Standard and XL)  
510504  
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6 Functional Specifications  
Restrictions for the MTBF Value  
The following types of failures are excluded from the calculation of  
MTBF:  
Failures arising from incorrect operating procedures  
Cable failures, power supply failures, or other failures not caused  
by equipment  
Failures caused by incorrect grounding procedures or by  
interference from external sources  
Media failures, or any failures or degraded performance caused  
by use of faulty or damaged media  
New failures that arise from continued use of a failed, misaligned,  
or damaged tape drive  
Failures caused by incorrect maintenance procedures, and all  
failures that occur within the first 40 power-on hours of any  
maintenance activity that includes the modification, adjustment,  
or replacement of any tape drive assembly  
Failures of new tape drives that occur within the first 40 power-on  
hours  
Data Integrity  
Conditions under which data integrity is maintained are as follows:  
No recorded data will be lost as a result of power loss while the  
tape drive is reading data.  
The tape drive will not record incorrect data to tape without  
posting an error condition.  
The tape drive will not return incorrect data to the system without  
posting an error condition.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-9  
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6 Functional Specifications  
Data Reliability  
Data reliability is specified as a bit error rate (BER) in units of one  
error per total number of bits transferred to the host.  
Conditions for Data Reliability  
The conditions under which the specifications for data reliability  
apply are as follows:  
The EXATAPE data cartridges used must comply with Standard  
ISO/ IEC 12246.  
Data cartridges must be written and read on a tape drive that is in  
good operating condition and properly grounded.  
Environmental conditions for the tape drive and the 8mm data  
cartridges must be maintained as specified in the “Environmental  
Specifications” section of this chapter.  
The tape drive must be cleaned with an Exabyte or  
Exabyte-approved 8mm cleaning cartridge using the  
recommended cleaning procedure. Refer to EXB-8205 and  
EXB-8505 Installation and Operation for instructions.  
Restrictions for Data Reliability  
The following types of errors are not included in the determination of  
data reliability:  
Errors caused by a failure of the tape drive  
Errors caused by faulty or damaged cartridges or media  
Errors caused by failure to comply with input power and  
grounding requirements, interference from external sources, or  
incorrect system operation or failure  
Errors corrected by the tape drives ECC  
Errors occurring in blocks other than blocks containing user data  
6-10  
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(Standard and XL)  
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6 Functional Specifications  
Write Reliability  
Write reliability is determined by the rate of permanent write errors.  
During a write operation, the tape drive uses read-after-write  
checking to determine whether physical data blocks are correctly  
written to tape. When the read-after-write check criteria are not met  
for a data block, the tape drive rewrites the block. The tape drive  
keeps track of the number of times blocks are rewritten and stores this  
number internally. The number is available through the REQUEST  
SENSE (03h) command and the LOG SENSE (4Dh) command.  
If the tape drive can rewrite the data block correctly, the error is a  
temporary write error, which does not affect write reliability. If,  
however, the tape drive cannot rewrite the data block correctly after a  
maximum of 11 rewrite attempts (12 write attempts total), the error is  
a permanent write error. When a permanent write error occurs, the  
tape drive returns Check Condition status.  
The rate for permanent write errors is as follows:  
–17  
Bit error rate:  
1.0 10  
Read Reliability  
Read reliability is determined by the rate of permanent read errors. If,  
during a read operation, the tape drive cannot read a block that has  
been correctly written, it attempts to reread the block. The tape drive  
keeps track of the number of times it attempts to reread a block and  
stores this number internally. This number is available through the  
REQUEST SENSE (03h) command and the LOG SENSE (4Dh)  
command.  
If the tape drive can reread the data block correctly, the error is a  
temporary read error, which does not affect read reliability. If,  
however, the tape drive cannot reread the data block correctly after  
one reread attempt at normal speed and one reread attempt at slow  
speed, the error is a permanent read error. When a permanent read  
error occurs, the tape drive returns Check Condition status.  
The rate for permanent read errors is as follows:  
–17  
Bit error rate:  
1.0 10  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-11  
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6 Functional Specifications  
Power Specifications  
This section lists the power specifications for the tape drive.  
Voltages  
The tape drive operates from standard +5 VDC and +12 VDC supply  
voltages, as specified in Table 6-7. All specified voltages are DC; no  
external AC power is used by the tape drive. The tape drive does not  
provide any overvoltage or overcurrent protection.  
Table 6-7 Power specifications for standard voltages  
Power specification  
+5 Volts  
+12 Volts  
Nominal tolerance:  
Ripple and Noise  
(60Hz to 20 MHz)  
a
±5% 125 mVpp max  
Operating current:  
b
Nominal  
SLDS card  
c
c
1.7A  
2.1A  
0.6A  
0.6A  
SLDD card  
d
Peak  
SLDS card  
SLDD card  
2.8A  
3.2A  
1.6A  
1.6A  
Operating power consumption:  
SLDS card  
14.5 watts  
16.5 watts  
SLDD card  
Power consumption when idle:  
SLDS card  
13.0 watts  
14.5 watts  
SLDD card  
a The ripple voltage is included in the total voltage tolerance.  
b Nominal current occurs during streaming write or read operation.  
c The SLDS card is the single-ended card; the SLDD card is the differential card.  
d The peak current occurs during load, unload, or at the start of search or rewind  
operations, and lasts for less than 1.5 seconds.  
Safety agency certification requires that the supplied voltages be from  
a Safety Extra-Low Voltage source (per IEC 950).  
6-12  
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(Standard and XL)  
510504  
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6 Functional Specifications  
Power Connector  
The power connector used in the tape drive is compatible with the  
power connector used for standard 5.25-inch, half-high devices.  
Figure 6-1 shows the location of the power connector on the rear of  
the tape drive and the pin assignments.  
Figure 6-1 Power connector location on the back panel  
Table 6-8 lists the pin assignments for the power connector.  
Table 6-8 Power connector pin assignments  
Pin Number  
Assignment  
1
2
3
4
+12 VDC  
Ground, 12 VDC return  
Ground, 5 VDC return  
+5 VDC  
To connect the tape drive to a power cable, use an AMP 1-480424-0  
series or equivalent female connector.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-13  
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6 Functional Specifications  
Grounding Hole and Ground Tab  
The rear panel of the EXB-8205 and EXB-8505 includes a grounding  
hole and a ground tab, as shown in Figure 6-2. These can be used to  
provide additional chassis grounding if desired. The grounding hole  
uses an M3 0.5 6mm self-tapping screw, while the ground tab uses  
1
a 4-inch female spade connector.  
Note: The power supply returns are connected to the chassis, so you  
cannot isolate logic common ground from chassis ground.  
Figure 6-2 Chassis ground location on back panel  
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6 Functional Specifications  
Environmental Specifications  
This chapter describes the following environmental specifications for  
the tape drive:  
Operating environment  
Air flow requirements  
Particulate contamination limits  
Shock and vibration specifications  
Acoustic noise limits  
Table 6-9 shows the overall environmental specifications for the tape  
drive.  
Table 6-9 Environmental specifications  
b
c
c
Specification  
Operation  
Storage or  
Transportation  
d
Not operating  
Temperature  
Range  
+5° C to + 40° C  
(+41° F to +104° F)  
–40° C to +60° C  
(–40° F to +140° F)  
–40° C to +60° C  
(–40° F to +140° F)  
a
Temperature  
Variation  
1° C per minute;  
1° C per minute;  
1° C per minute;  
e
max 10° C per hour  
(2° F per minute;  
max 18° F per hour)  
max 20° C per hour  
(2° F per minute;  
max 36° F per hour)  
max 20° C per hour  
(2° F per minute;  
max 36° F per hour)  
Relative  
Humidity  
20% to 80%  
Non-condensing  
10% to 90%  
Non-condensing  
10% to 90%  
Non-condensing  
e
Wet Bulb  
Altitude  
26°C (79°F) max  
–304.8 m to +3,048 m –304.8 m to +3,048 m  
–304.8 m to +12,192 m  
(–1,000 ft to +10,000 ft) (–1,000 ft to +10,000 ft) (–1,000 ft to +40,000 ft)  
a
b
c
d
e
The temperature specifications assume that temperature measurements are made at the tape path.  
All operating measurements include an EXATAPE data cartridge.  
The tape drive has not been unpacked. Data cartridges are not packed with the tape drive.  
The tape drive has been unpacked but is not operating. The data cartridge is not included.  
The data cartridge’s temperature and humidity must be allowed to stabilize in the specified ambient  
environment for 24 hours.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-15  
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6 Functional Specifications  
Operating Environment  
The psychrometric chart, Figure 6-3, shows the operating temperature  
and humidity ranges for the tape drive. The dotted line represents the  
operating environment.  
Table 6-10 defines the temperature and humidity points shown in  
Table 6-10 Temperature and humidity specifications  
Point  
Temperature  
5° C  
Humidity  
80%  
A
B
C
D
E
80%  
29° C  
34%  
40° C  
20%  
40° C  
20%  
5° C  
Figure 6-3 Temperature and humidity ranges for operation  
6-16  
EXB-8205 and EXB-8505  
(Standard and XL)  
510504  
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6 Functional Specifications  
Air Flow Requirements  
Adequate air flow must be provided in the enclosure for the tape  
drive to dissipate heat resulting from approximately 15.0 watts of  
power consumption. The air flow around the entire tape drive must  
be sufficient to prevent the tape path temperature from exceeding  
40° C (104° F). However, air flow within the enclosure must be  
minimal at the tape path. Otherwise, particulate contamination of the  
media can result.  
Particulate Contamination Limits  
The ambient operating environment should not exceed the particulate  
counts shown in Table 6-11.  
Table 6-11 Particle contamination limits  
Particle  
Size  
(microns)  
Number of Particles ≥  
Particle Size per Cubic  
Meter  
Number of Particles ≥  
Particle Size per Cubic  
Foot  
7
6
0.1  
0.5  
5.0  
8.8 10  
2.5 10  
7
6
3.5 10  
1.0 10  
5
3
2.5 10  
7.0 10  
Figure 6-4 shows the particulate contamination profile of a typical  
office compared to the specifications for the tape drive.  
Contamination profiles of individual office areas vary.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-17  
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6 Functional Specifications  
Figure 6-4 Particulate contamination specification vs. typical office  
Shock Specifications  
Table 6-12 lists the shock specifications for the tape drive. The  
operating shock levels indicate how much shock the tape drive can  
withstand while it is reading and writing data. The non-operating and  
storage shock levels indicate how much shock the tape drive can  
withstand when it is not operating. After withstanding this amount of  
shock, the tape drive will operate normally.  
Table 6-12 Shock specifications  
a
b
a
Operating  
Storage or Not Operating  
Transportation  
NSTA Project 1A  
c
3 g for 5 ms  
45 g at a velocity change of  
192 inch/sec  
d
a The tape drive has not been unpacked.  
b The tape drive has been unpacked, but no power has been applied.  
c A minimum of 20 shock pulses were applied to each of the three orthogonal axes.  
The shock pulses were half-sine waves and were applied at a rate not exceeding  
one shock per second.  
d A minimum of three trapezoidal shock pulses of 45 g were applied to each of the  
tape drive’s six sides at a velocity change of 192 inches per second (equivalent  
height equals 48 inches).  
6-18  
EXB-8205 and EXB-8505  
(Standard and XL)  
510504  
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6 Functional Specifications  
Vibration Specifications  
Table 6-13 lists the vibration specifications for the tape drive during  
operation, non-operation, storage, and transportation. The operating  
specifications listed in this table indicate the amount of vibration that  
the tape drive can withstand while reading and writing data.  
Table 6-13 Vibration specifications  
a
Random vibration applied during operation  
2
1 Hz  
PSD = 0.000003 g /Hz  
2
5 Hz  
PSD = 0.00002 g /Hz  
2
10-150 Hz  
200-400 Hz  
PSD = 0.0003 g /Hz  
2
PSD = 0.00008 g /Hz  
b
c
d
Random vibration applied during non-operation and storage  
2
1 Hz  
PSD = 0.0003 g /Hz  
2
3 Hz  
PSD = 0.00055 g /Hz  
2
12-100 Hz  
PSD = 0.01 g /Hz  
2
400 Hz  
PSD = 0.000003 g /Hz  
d
Transportation  
NSTA Project 1A  
a A 0.3 g RMS random vibration spectrum is applied to each of three orthogonal axes  
for a minimum of 20 minutes per axis.  
b A 1.06 g RMS random vibration spectrum is applied to each of three orthogonal  
axes for a minimum of 20 minutes per axis.  
c The tape drive has been unpacked, but is not operating.  
d The tape drive has not been unpacked.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
6-19  
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6 Functional Specifications  
Acoustic Noise  
The overall, averaged A-weighted sound power levels (decibels) for  
the tape drive do not exceed the upper limits specified in Table 6-14.  
Table 6-14 Acoustic noise limits  
Operating mode  
LWA*  
The tape drive is powered on and idle.  
40 dBA  
The tape drive is fully operational and operating in  
streaming mode for a read or write operation.  
45 dBA  
L
* WA is the average A-weighted sound power level over the following frequency  
range: 5 Hz to 12.5 KHz.  
6-20  
EXB-8205 and EXB-8505  
(Standard and XL)  
510504  
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7
Safety and Regulatory  
Agency Compliance  
This chapter describes the following:  
Safety agency standards  
Electrostatic discharge (ESD) standards  
Electromagnetic compatibility (EMC)  
Radiated susceptibility  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
7-1  
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7 Safety and Regulatory Agency Compliance  
Safety Agency Standards  
When purchased from Exabyte Corporation, the tape drive is certified  
as a component by the following domestic and international product  
safety standards.  
UL Standard 1950, 1st Edition, Information Technology  
Equipment  
CAN/ CSA Standard C22.2 No. 950-M89, Safety of Information  
Technology Equipment  
IEC 950/ EN60950, Safety of Information Technology Equipment  
including Electrical Business Equipment (TUV)  
Certification of the final product is the responsibility of the system  
integrator.  
Electrostatic Discharge (ESD)  
When properly installed with a shielded cabinet, shielded cables, and  
adequate grounding of the SCSI bus and the input power, the tape  
drive can withstand discharges of the following:  
Up to 10,000 volts applied to those points that are accessible  
during normal use without affecting the permanent read error  
rate or requiring operator intervention.  
Up to 15,000 volts applied to those points that are accessible  
during normal use without sustaining permanent damage.  
However, at this level of discharge, operator intervention may be  
required to reset the tape drive.  
Note: No errors will occur or damage be caused to the tape drive  
when a cartridge charged to a maximum of 20,000 volts is  
inserted into the tape drive.  
7-2  
EXB-8205 and EXB-8505  
(Standard and XL)  
510504  
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7 Safety and Regulatory Agency Compliance  
Electromagnetic Compatibility (EMC)  
When properly installed with a shielded cabinet, shielded cable and  
adequate grounding of the SCSI bus and the input power, the tape  
drive meets the requirements for radiated and conducted emissions as  
defined by the following standards:  
FCC Rules, Part 15, Class B Computing Devices  
Canadian Department of Communications, Radio Interference  
Regulation for Digital Apparatus, Class B  
VDE Vfg 1046/ 1984, Class B  
CISPR Publication 22, 1985, Class B  
Radiated Susceptibility  
When properly installed with a shielded cabinet, shielded cables, and  
adequate grounding of the SCSI bus and the input power, the tape  
drive will continue to operate without error when subjected to  
electromagnetic energy of severity level 2 (3 volts/ meter) as defined  
by IEC Publication 801-3.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
7-3  
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7 Safety and Regulatory Agency Compliance  
Notes:  
7-4  
EXB-8205 and EXB-8505  
510504  
(Standard and XL)  
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Glossary  
One of the data formats written and read by the  
EXB-8205, EXB-8205XL, EXB-8505, and  
EXB-8505XL. Tapes written in 8200 format can also  
be read by any EXB-8200, EXB-8200SX, EXB-8500, or  
EXB-8500c.  
8200 format  
One of the data formats written and read by the  
EXB-8205, EXB-8205XL, EXB-8505, and  
EXB-8505XL. Tapes written in 8200c format can also  
be read by an EXB-8500c.  
8200c format  
8500 format  
8500c format  
One of the data formats written and read by the  
EXB-8505 and EXB-8505XL. Tapes written in 8500  
format can also be read by an EXB-8500 or  
EXB-8500c.  
One of the data formats written and read by the  
EXB-8505 and EXB-8505XL. Tapes written in 8500c  
format can also be read by an EXB-8500c.  
American National Standards Institute.  
Beginning of tape.  
ANSI  
BOT  
Initiator or target devices connected to the SCSI bus.  
Eight bits or one character.  
bus devices  
byte  
Celsius (Centigrade).  
C
Canadian Department of Communications.  
Centimeter (0.3937 inches).  
Canadian DOC  
cm  
The establishment of communications between the  
initiator and the selected target.  
connect  
Cyclic redundancy check.  
CRC  
CSA  
CTS  
Canadian Standards Association.  
Cartridge Tape Subsystem. Also referred to as a  
tape drive.  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
G-1  
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Glossary  
The termination of communications between the  
initiator and the target. During a disconnect, the  
target releases control of the SCSI bus, allowing the  
bus to become free.  
disconnect  
Error correction code.  
ECC  
ECMA  
European Computer Manufacturers Association.  
Electrically erasable programmable read only  
memory.  
EEPROM  
Erasable programmable read only memory.  
End of data.  
EPROM  
EOD  
End of tape.  
EOT  
A data-grade, rewriteable data cartridge.  
EXATAPE  
EXB-8200  
The EXB-8200 8mm Cartridge Tape Subsystem. The  
EXB-8200 can store up to 2.5 gigabytes of data on a  
single EXATAPE 8mm data cartridge.  
The EXB-8200SX 8mm Cartridge Tape Subsystem.  
The EXB-8200SX is very similar to the EXB-8200 but  
offers a high-speed search capability.  
EXB-8200SX  
EXB-8205  
The EXB-8205 8mm Cartridge Tape Subsystem. The  
EXB-8205 is a half-high 8mm cartridge tape  
subsystem that can store 5 gigabytes of data on a  
single EXATAPE 112m 8mm data cartridge,  
assuming an average 2:1 compression ratio.  
The EXB-8205XL 8mm Cartridge Tape Subsystem.  
The EXB-8205XL is a half-high 8mm cartridge tape  
subsystem that can store 7 gigabytes of data on a  
single EXATAPE 160m XL 8mm data cartridge,  
assuming an average 2:1 compression ratio.  
EXB-8205XL  
The EXB-8500 8mm Cartridge Tape Subsystem. The  
EXB-8500 can store up to 5 gigabytes of data on a  
single EXATAPE 112m 8mm data cartridge.  
EXB-8500  
The EXB-8500c 8mm Cartridge Tape Subsystem.  
The EXB-8500c is physically similar to the  
EXB-8500c  
EXB-8500, but offers data compression as an option.  
Assuming an average compression ratio of 2:1, the  
EXB-8500c can store up to 10 gigabytes of data on a  
single EXATAPE 112m 8mm data cartridge.  
G-2  
EXB-8205 and EXB-8505  
510504  
(Standard and XL)  
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Glossary  
The EXB-8505 8mm Cartridge Tape Subsystem. The  
EXB-8505  
EXB-8505 is a half-high 8mm cartridge tape  
subsystem that can store 10 gigabytes of data on a  
single EXATAPE 112m 8mm data cartridge,  
assuming an average 2:1 compression ratio.  
The EXB-8505XL 8mm Cartridge Tape Subsystem.  
The EXB-8505XL is a half-high 8mm cartridge tape  
subsystem that can store 14 gigabytes of data on a  
single EXATAPE 160m XL 8mm data cartridge,  
assuming an average 2:1 compression ratio.  
EXB-8505XL  
Fahrenheit.  
F
FCC  
Federal Communications Commission.  
Flash erasable programmable read only memory.  
Gigabyte.  
FEPROM  
GByte  
h
Hexadecimal (base 16) numbering system.  
The computer system that acts as the initiator of an  
operation.  
host  
Hertz.  
Hz  
ID  
Identification.  
Improved Data Recording Capability. The  
compression algorithm used by the EXB-8205,  
EXB-8205XL, EXB-8505, and EXB-8505XL (licensed  
from IBM).  
IDRC  
International Electrotechnical Commission.  
IEC  
A host computer system that requests an operation  
to be performed by the target.  
initiator  
International Standards Organization.  
Kilobyte.  
ISO  
KByte  
LBOT  
LEOT  
LUN  
Logical beginning of tape.  
Logical end of tape.  
Logical unit number.  
Megabyte.  
MByte  
MLCH  
Machine level control history.  
May 1994  
EXB-8205 and EXB-8505  
G-3  
(Standard and XL)  
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Glossary  
Millimeter (0.03937 inches).  
Millisecond.  
mm  
ms or msec  
ns  
Nanosecond.  
National Safe Transit Association.  
Physical beginning of tape.  
Physical end of tape.  
NSTA  
PBOT  
PEOT  
Power-on self-test; the process that occurs when the  
tape drive performs its initial power-on diagnostics.  
POST  
The state of the tape drive when it is ready to  
process commands.  
ready  
The function that occurs when the target arbitrates  
and reconnects to an initiator after a disconnect.  
reconnect  
Small Computer System Interface.  
SCSI  
An octal representation of the unique address (0-7)  
assigned to a SCSI device.  
SCSI address  
Driving a signal to the true state.  
signal  
assertion  
Driving a signal to the false state or biasing the  
signal by the cable terminators to the false state.  
signal  
de-assertion  
When a signal is not driven by a bus but is biased  
by the cable terminators to the false state.  
signal  
release  
Information sent from the target to the initiator  
upon completion of a command.  
status  
A bus device (usually a controller) that performs an  
operation requested by an initiator. The tape drive  
is a target.  
target  
Extended length.  
XL  
µm  
Micrometer (0.00003937 inches).  
Microsecond.  
µs or µsec  
G-4  
EXB-8205 and EXB-8505  
510504  
(Standard and XL)  
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D
data cartridges  
Index  
track and block counts 2-20  
A
data compression  
See compression  
data reliability  
B
bit error rate  
blocks  
differential SCSI  
C
cleaning the tape drive  
compression  
E
electromagnetic interference, susceptibility to  
EXATAPE data cartridges  
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
I-1  
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Index  
F
M
filemarks  
mean time between failures  
formats, data  
motion threshold  
G
MTBF  
See mean time between failures  
N
H
heads  
O
I
P
IDRC algorithm  
See compression  
physical block counts 2-20  
physical blocks  
L
LEDs  
logical blocks  
pin assignments  
I-2  
EXB-8205 and EXB-8505  
(Standard and XL)  
510504  
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Index  
R
T
tape speed  
reconnect threshold  
thresholds  
S
SCSI  
U
SCSI commands  
SCSI ID  
V
single-ended SCSI  
W
May 1994  
EXB-8205 and EXB-8505  
(Standard and XL)  
I-3  
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Index  
Notes:  
I-4  
EXB-8205 and EXB-8505  
510504  
(Standard and XL)  
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