Tandberg Data TDC 3640 User manual

--- -- - ~ - ~ -~ -:-:-::-------~------
~ .
l
TANDBERG DATA ==
TDC 3600 SERIES "
STREAMING TAPE CARTRIDGE DRIVES
r
Toe 3620/3640/3660
Reference Manual

Table of Contents
o.
1.
1.1.
1.2.
1.3.
2.
2.1.
2.2.
2.3.
2.4
2.5.
2.6.
3.
31.
3.2.
3.3.
3.31.
3.3.2.
3.33
3.34.
3.3.5.
34.
3.4.1.
3.4.2.
3.4.3.
3.4.4.
3.4.5.
3.4.6.
3.5.
3.5.1.
3.5.2.
3.5.3.
3.6.
3.6.1.
3.6.2.
3.6.3.
3.6.4.
3.6.5.
3.6.6.
3.6.7.
3.6.8.
3.6.9.
3.6.10.
4.
4.1.
4.2.
4.2.1.
4.2.2.
4.2.3.
4.2.4.
4.2.5.
4.3.
4.4.
Preface ....................................................................................................................
0·1
,
About this Manual .................................................................................................. 1·1
Definitions ........................................................................................................... 1 ·1
Introduction to this Manual .................................................................................. 1-'
Additional Documentation ................................................................................... '·2
Introduction to the Drive ....................................................................................... 2·1
Summary ............................................................................................................. 2·'
General Drive Description ................................................................................... 2·1
Tape Format and Drive Operation ...................................................................... 2·3
Drive Block Diagram with Description ................................................................. 2·5
The Formatter Functions .................................................................................... 2·6
Interface to Host ................................................................................................. 2-7
Ffroduct Specifications .......................................................................................... 3·1
Mechanical Dimensions and Weight ................................................................... 3-1
Power Requirements .......................................................................................... 3-1
Environmental Specifications .............................................................................. 3·2
Temperature and Relative Humidity .............................................................. 3·2
Temperature Variation ................................................................................... 3-3
Atmospheric Pressure .................................................................................... 3·3
Vibration ......................................................................................................... 3·3
Impact and Shock .......................................................................................... 3-3
Product Performance Specifications ................................................................... 3-4
Audible Noise ................................................................................................. 3-4
Radiated Electromagnetic Interference ..........................................................3-4
Susceptibility to Electromagnetic Interference ............................................... 3-4
Static Discharge ............................................................................................. 3-4
Safety Standard ............................................................................................. 3-4
Mean Time to Repair ..................................................................................... 3-4
Product Reliability ............................................................................................... 3·5
Electronics MTBF ........................................................................................... 3-5
Mechanics MTTF .... ................................ ...... ............................................ ..... 3-5
Useful life Cycle ............................................................................................ 3-5
Functional Specifications .................................................................................... 3-6
Media ............................................................................................................. 3-6
Track Width and location .............................................................................. 3-6
Head Specifications ....................................................................................... 3-9
Tape Movement ............................................................................................. 3-9
Recording Specifications ............................................................................. 3·10
Storage Capacity ......................................................................................... 3-11
Head Moving Mechanism ............................................................................ 3-11
Capstan System .......................................................................................... 3-11
Tape Sensor System ................................................................................... 3-11
Electronics ................................................................................................... 3-12
Mounting Specifications ....................................................................................... 4·1
General Mounting Information ............................................................................. 4-1
Strap Setting/Selecting Drive Number ................................................................ 4-3
Selecting Drive Number .................................................................................4·3
EnablelDisable Bus Parity Checking ............................................................. 4-4
External SCSI·bus Termination ..................................................................... 4-4
Serialln/Out Communication .........................................................................4·5
Test Functions ............................................................................................... 4·5
SCSI·Bus Interface Configuration ....................................................................... 4-6
Heat Dissipation .................................................................................................. 4-7
i

5. Data Reliability ....................................................................................................... 5-1
5.1. Summary ............................................................................................................. 5·1
5.2. General Introduction ............................................................................................ 5·1
5.3. Write Mode .......................................................................................................... 5·2
5.4. Read Mode ......................................................................................................... 5·3
5.5. Cartridge Conditioning ......................................................................................... 5-4
6. Track, Tape-fonnat and Encoding Specifications .............................................. 6-1
6.1. Summary ............................................................................................................. 6-1
6.2. Track Specifications ............................................................................................ 6-1
6.3. Track Format. OIC-24, OIC-120 and OIC-150 .................................................... 6-4
6.4. Recording Method .............................................................................................. 6-4
6.5. Data Encoding ..............................................................:..................................... 6-4
6.6. Recording Sequence ........................:................................................................. 6-6
6.7. Block Layout OIC-11 and OIC-24/0IC-120/0IC-150 .......................................... 6-7
6.7.1. Preamble ........................................................................................................ 6-7
6.7.2. Block Marker .................................................................................................. 6-8
6.7.3. Data ................................................................................................................ 6-8
6.7.4. Block Address ................................................................................................ 6-9
6.7.5. CRC (Cyclic Redundancy Check) ............................................................... 6-10
6.7.6. Post amble .................................................................................................... 6-10
6.8. Rewriting of Blocks ......................:..................................................................... 6·11
6.9. File Mark Blocks ............................................................................................... 6-12
6.10. Control Blocks ................................................................................................... 6-13
6.11. Gaps ................................................................................................................. 6-13
6.12. Reference Burst ................................................................................................ 6-14
6.13. Termination after Underrun ............................................................................... 6-14
6.14. Data Append ..................................................................................................... 6-14
6.15. Recording of Even Numbered Tracks ............................................................... 6·14
6.16. Recording of Odd Numbered Tracks ................................................................ 6·15
7. Basic Operational Functions ................................................................................ 7·1
7.1. Reference Track ................................................................................................. 7·1
7.1.1. Write Reference Track ................................................................................... 7-1
7.1.2. Read Reference Track ................................................................................... 7-2
7.2. Write Data and Filemarks ....................................................................................7·3
7.2.1. Write From Beginning of Tape ....................................................................... 7·3
7.2.2. Write From a Position on the Tape ................................................................ 7·3
7.2.3. Terminate Write From a Position on the Tape ............................................... 7-4
7.2.4. Terminate Write at Physical End Of Tape ..................................................... 7·4
7.2.5. Terminate Write at Physical End Of Tape -Executing the Copy Command. 7·5
7.2.6. Recoverable Write Error (Rewrite) ................................................................. 7-5
7.2.7. Unrecoverable Write Error ............................................................................. 7-6
7.3. Read Data and Filemarks ................................................................................... 7-7
7.3.1. Read From Beginning of Tape ....................................................................... 7·7
7.3.2. Read From a Position on the Tape ................................................................ 7·7
7.3.3. Read Until Logical End Of Tape .................................................................... 7-7
7.3.4. Read Until Physical End Of Tape .................................................................. 7-7
7.3.5. Read Until Physical End Of Tape - Executing the Copy Command .............. 7·8
7.3.6. Recoverable Read Error (Reread) ................................................................. 7·8
7.3.7. Unrecoverable Read Error ............................................................................. 7-8
8. Hardware Interface .................................................................................................. 8-1
8.1. Power Interface ................................................................................................... 8·1
8.2. Introduction to the Signal Interface ..................................................................... 8·1
8.3. Definition of Terms .............................................................................................. 8-1
8.4. Electrical Interface ...............................................................................................8·2
8.4.1. Drive Interface Connector Layout .................................................................. 8·3
8.4.2. Bus Signals ... _...............................................................................: .. :........... :. 8-4.
ii

8.5.
8.5.1.
8.5.2.
8.5.3.
8.5.4.
8.5.5.
8.5.6.
8.5.7.
8.5.8.
8.5.9.
8.5.10.
8.6.
8.6.1.
8.6.2.
8.6.3.
8.6.4.
9.
9.1.
9.2.
9.3.
9.3.1.
9.3.1.1.
9.3.1.2.
9.3.1.3.
9.3.1.4.
9.3.1.5.
9.3.2.
9.3.3.
9.3.4.
9.3.5.
9.3.6.
9.3.7.
9.3.8.
9.3.8.1.
9.3.9.
9.3.10.
9.3.11.
9.3.12.
9.3.13.
9.3.14.
9.3.14.1.
9.3.14.2.
9.3.15.
9.3.16.
9.3.17.
9.3.18.
9.3.19.
9.3.20.
9.3.21.
9.3.21.1.
9.3.22.
9.3.22.1.
9.3.23.
9.3.24.
9.4.
9.5.
9.6.
9.7.
9.7.1.
Bus Phases ......................................................................................................... 8·5
Bus Free Phase ............................................................................................. 8·5
Arbitration Phase (Optional) .......................................................................... 8-5
Selection Phase .....................................................................:....................... 8·6
Reselection Phase (Optional) ........................................................................ 8-7
Command Phase ........................................................................................... 8·8
Data Exchange Phase ................................................................................... 8-9
Status Phase ............................................................................................... 8·' 0
Message In Phase ....................................................................................... 8·"
Message Out Phase........................... ..... .................................................... 8·'2
Summary of SCSI·bus Phases .................................................................... 8·' 3
Bus Conditions .................................................................................................. 8·'4
Attention Condition ....................................................................................... 8· 14
Unit Attention Condition ............................................................................... 8·'4
Reset Condition.......... ........ ........ ........ ......................................................... 8· 14
Phase Sequencing ........................................................................................ 8·15
Software Interface .................................................................................................. 9·1
Introduction .....................................................................................:................... 9·'
Command Descriptor Block ................................................................................ 9·'
Drive Command Set ........................................................................................... 9-3
Copy (18H) ..................................................................................................... 9·4
Command and Parameter Blocks ............................................................ 9·5
Copy Operation .............................................................................._......... 9·8
Block Sizes ............................................................................................ 9·10
Error Handling ......................................................................................... 9· l'
Command Descriptor Blocks Used as an Initiator .................................. 9·15
Erase (19H) ................................................................................................. 9·17
Inquiry (12H) ................................................................................................ 9·18
Load/Unload (1BH) ...................................................................................... 9·21
Mode Select (15H) .......................................................................................9·22
Mode Sense (1AH) ...................................................................................... 9·27
PrevenvAllow Media Removal (1 EH) ...........................................................9·30
Read (08H) .................................................................................................. 9·31
Read Command Error Conditions .......................................................... 9·32
Read Block Limits (OSH) .............................................................................. 9·33
Read Data Buffer (3BH) .............................................................................. 9·34
Recover Buffered Data (14H) ...................................................................... 9·36
ReJease Unit (17H) ...................................................................................... 9·37
Request Block Address (02H) ..................................................................... 9·38
Request Sense (03H) .................................................................................. 9·39
Standard Sense Status Block ................................................................. 9·40
Extended Sense Status Block ................................................................ 9·42
Reserve Unit (16H) ......................................................................................9·48
Rewind (01 H) ............................................................................................... 9·49
Seek Block (OCH) ........................................................................................ 9·50
Send Diagnostics (1DH) .............................................................................. 9·51
Space (11H) ................................................................................................. 9·53
Test Unit Ready (OOH) ................................................................................. 9·55
Verify (13H) ..................................................................................................9·56 '
Verify
Command Error Conditions ..........................................................9·57
Write (OAH) .................................................................................................. 9·58
Write Command Error Conditions ........................................................... 9·59
Write Data Buffer (3CH) .............................................................................. 9·60
Write File Mark (1 OH) .......................:........................................................... 9·61
Completion Status Byte ..................................................................................... 9-62
The Message·ln Byte ........................................................................................ 9-63
The Message·Out Byte ..................................................................................... 9-64
Parity Error Handling .........................................................................................9·65
General'
Information ..... ;.......:...................:.,.: .......... : ...... ,.: .......................... :., 9~6.5 .
Hi

10.
10.1.
10.1.1.
10.1.2.
10.1.3.
10.2.
Selftest and Preventive Maintenance ••••••••••••••• __ .............................................., ().1
Selftest .............................................................................................................. 10·'
Power·Up SelftestlSeHtest 1........................................................................ 10·'
The Manually Activated Selftests ................................................................. , 0·3
The Host Activated Selftests ...................................................................... , 0·5
Preventive Maintenance ................................................................................... 10·6
Appendix A: Extended Error Code Messages ..................................................................... A·,
Appendix B: General Error Conditions................................................................................. B·1
AppendIx
C: Application Notes......_.........._....... ____ ........................................................ C·,
C.1. How to Achieve Streaming Mode Operation ...................................................... C·,
C.2. If Streaming Mode can not be Achieved .............................................................C-2
C.3. How to Optimize SCSI
Per10rmance .................................................................. C-4
Appendix 0: Internal Buffer Operation .................................................................................0·1
D.' . Data Buffer Design Goal .....................................................................................0-1
0.2. Data Buffer Operation ........................................................................................ 0-2
iv

TANDBERG DATA 0-1 Preface
o. Preface
This is the reference manual for the mc 3620/3640/3660 SCSI
("Smail Computer System Interface") compatible streaming 1/4"
tape cartridge drive. .
Tandberg Data will appreciate any comments on this publication
regarding:
• discrepancies between specification and product
• Inconsistency of definitions
• lack
of clarity In the definitions
• QIC·", QlCo24, QlCo120 and QICo150 compatibility
• QIC-104 compatibility
• SCSI Comm~nd Set compatibility to ANSI, Revision 178
• Emulex MT03 Controllercompatibility where this Is not In
conflict with ANSI Revision
178
Incompatibilities to MT03 8re85 follows:
The Copy Command supports only copy between Direct
Access and a Sequential Access Drive.
The Mode Select command does NOT suppon the EMULEX
Vendor Unique bits:
DEA: Disable Area Ahead
AU]: Auto Load Inhibit
SEC: Soft Error Count
The following Extended Sense Status Bytes have changed
position:
ERClJERCD: Moved from byte 08 to byte 14 Number Of
Recoverable Enors: Moved from bytes 09 and J0 to bytes
12 and 13.
The TDC3620/40/60 Drive does NOT suppon the command:
Read Revision Level
The IMED (Immediate) bit for the Verify command is NOT
supponed as the TDC3620/40/60 Drlvehandles this as a
Read-type command.
The1DC3620/40/60 Drive requires aFile Mark written as ·the
last block of every recording. Failure to this will ciuse 24
rereads and Unrecoverable Data Error during the Read
command.

TANDBERG DATA
0-2
Preface
IMPORTANT!
Tape is a very hygroscopic media. If exposed to a high humidity environment
oversome period,
it may require several days to bring a cartridge back to normal
humidity condition, even ifthe humidity level during
this" dry-out" period is kepI
very low. An environment with a high humidity like this may not only occur in
areas with a natural high humidity.
A typical example may be a cartridge placed in its packaging box
and cooled
down during transportation. The relative humidity inside the box may increase;
and over time affect the relative humidity of the tape itself.
Running high humidity tapes over a long period
of time may se\'erely reduce the
life time
of the drive's ReadlWrite head. It may also drastically reduce the life
time
of the tape.
If in doubt, always let a cartridge "dry out" in a normal humidity em'ironment
« 50-65 % rei. hum. at +20°C) for at least 3·4 days prior to use.
The head life time specifications stated by Tandberg Data A/S assumes running
tapes in
an environment with an average reI. hum. of not more than 50 % and a
maximum
of not more than 65 %; aU at a temperature of not more than +30°C
outside the cartridge.
Relative humidities
up to 80 % are assumed only for a maximum of 1 hour for
-every 24 hours of tape running. Maximum relative humidity of the em'ironments
shall not be more than 50 % averaged over the life cycle test, and never more
than 65 %,averaged over 200 running hours.
The head life time specifications given for this product is not valid if the drive has
been used in envir«:lnments •
or with tapes· that cannot meet the specificatic,JDs
above. . . " ,,'
Tandberg Data AlS does not warrant against failure of any tape drive product
that has directly or indirectly been exposed to conditions outside the specifications
given above.

TANDBERG DATA
Chapter2
Chapter3
Chapter 4
ChapterS
1-1
About This Manual
1. About this Manual
1.1. Definitions
The following two tenns are widely used throughout this
manual:
"The Drive"
Refers to the half-
height SCSI ("Small
Computer System
Interface") compa-
tible TDC 3620 9-
track, TDC 3640
15-
track and IDC 3660
I8-track Drive.
"The Host"
Refers to the host computer that suppons the SCSI hardware and
software specifications, and thus is able to control the SCSI
compatible IDC 3620/40/60 Drive.
1.2. Introduction to this Manual
This manual is intended to be the main reference document for
users, system programmers and system integrators
of the IDC
3620/40/60 streaming 1/4" tape cartridge drive.
The mc 3620 Drive complies with the SCSI Interface
Standard. and the QIC-24 Data Interchange Standard.
The TDC 3640 and the
IDC 3660 Drives comply respectively
with the QIC-120 or the QIC-150 Data Interchange Standards
in
addition to the SCSI specifications.
The
IDC 3620, the IDC 3640 and the IDC 3660 reads and
writes nine, fifteen
or eighteen tracks serially, running the tape at
90 ips or 72 ips respectively.
Detailed circuit-board block diagrams, schematics and adjust-
ment procedures are not supponed by this manual. The field
service technician will need the TDC
3600 Series SCSI
.Maintenance Manual, in addition to this reference manual,
in
order to have the complete service documentation at hand.
describes the basic features
of the Drive accompanied by a block
diagram
..
gives the technical specifications in detail.
contains mounting specifications.
describes data reliability and tape conditioning.

TANDBERG DATA
Chapter6
Chapter7
Chapter 8
Chapter 9
1·2
About This Manual
describes the tape formats (9, 15 and 18 tracks) and how the data
is encoded.
describes the Drive's supponed basic operational functions.
describes the interface of the Drive with regards to the hardware.
is a comprehensive description of the interface to the Drive
regarding software and/or system. It describes the command set
and the behavior of the Drive in various situations.
1.3. Additional Documentation
SCSI (Small Computer System Interface manual) ANSI X3.131
Standard, Revision 17B, 1986.
The QIC-24 and QIC-02 Standards, Revision D, (Part no.
402732, Publ.no.S447), available from our Sales Department.
The QIC-120 Standard for Data Interchange, Revision 0,
February II. 1987.
The QIC-I SO Standard for Data Interchange, Revision I, May
12. 1987.

TANDBERG DATA
TheTDC 3620
The
TOC 3640
TheTOC 3660
2·1 Introduction to the Drive
2. Introduction to the Drive
2.1. Summary
This chapter describes the basic features of the Tandberg Data
mc 3620/40/60 streaming tape cartridge drive. After a general
introduction. a description
of the mechanical and electrical drive
design is given.
2.2. General Drive Description
The Tandberg Data TOC 3620/40/60 is a streaming 1/4" tape
cartridge drive.
The TOC 3620 records and reads serially on 9 tracks and can
store 45 Mbytes on a
137 m (450-foot) cartridge. With the 169
m (555-foot) cartridge the capacity is increased to 55 Mbytes.
The 183 m (6oo-foot) cartridge gives a capacity
of up to 60
Mbytes.
The
mc 3640 records and reads serially on 15 tracks and can
store 125 Mbytes on a 183 m (600-foot) cartridge.
The IDC 3660 records and reads serially on 18 tracks and can
store
155 Mbytes on a 183 m (600-foot) cartridge.
Drive Application
The Drive is well suited for a variety of applications:
-Winchester back-up
-Archival storage
-Low cost background mass-storage system
-Data logging
-Replacing the floppy disk for data interchanges
Streaming
The mode of operation is streaming. i.e. the Drive is designed to
run the whole length
of the tape. normally without any
interruption. Unnecessary stan and stop operations in the middle
of the tapes will slow down the system considerably.
Basic Mechanical Building Blocks
The Drive mechanism is built inside a rigid casting. The
mechanism includes a direct-drive capstan motor. a door-locking
and ejection system and a head-moving ("worm-wheel/gear")
system. Figure
2.1 illustrates the Drive's mechanical outline.
Note that mounting the drivetpp-jlush against a/lat sUrface. will
impede air /low and may obstruct the rubber impeller-fan
mounted on the capstan-motor axle.

TANDBERG DATA
2-2
Figure 2.1 The Drive
The ElectronIcs
Introduction to the Drive
The electronics are contained on two printed circuit boards: The
Mainboard and the Sensorboard.
The Drive electronics comprises the 68
HCll microcomputer
and two custom made Tandberg Data ASIC-circuits: one
handling the Drive's fonnatting functions and the other handling
the bufferand bus-interface circuitry.
All electronics except the opta-electronic tape hole sensors, the
mechanical "cartridge-in-pJace" and "write protected" switches
are situated on the Mainboard. The exceptions mentioned are
located on the Sensorboard.

TANDBERG DATA
Data Block
n~
.
Preamble
2·3 Introduction
to the Drive
2.3. Tape Format and Drive Operation
Data is formatted into small blocks, each block containing 512
bytes
of data. Special address and checking bytes are added to
each block. The basic layout is shown in Figure 2.2. The
overhead per block is very small, nominally 19.5 bytes.
Data Block Cpntrol Block Data Block
(File Mark)
n+1
n+2 n+3
Data Dafa
Block CRe Postamble
Marker Address
(512 bytes)
Standard Data Block
Figure 2.2 Track/onnat
Write Operation
The data bytes are transferred from the Host to the Drive and
stored in the Drive's data buffer. The data is assembled into
blocks of 512 bytes. The Drive adds special address and check
characters to each block prior to writing the complete block on
the
tape. The blocks are written without the traditional long
interblock gaps. The Drive performs read-after-write checking,
and blocks with errors are automatically rewritten funher down
the
tape.
Read Operation
In read mode. data is read from the tape and the formatter-ASIC
strips
off the special address and check characters. The data
bytes are then transferred to the Host via the built-in data buffer
in the Drive.
EdgelReference Track Seeking
In order to improve the track-location accuracy and to ensure
data interchangeability between canridges. the Drive uses the
edge
of the tape as the basic reference during write mode and
special reference signals as references during read operations.
When changing tracks the head will always move upwards when
the new
tracki~ entered. This is done toeUminate influence of
so-called "backlash" in the "wonn-gear". "

TANDBERG DATA
2-4 Introduction
to the Drive
Track Seek'ng In Write Mode
When the Drive has received the write command, it steps the
head down until the forward (lower) recording channel is right
above the lower tape edge. The tape is at BOT. Then the Drive
starts moving the tape forward, and at the same time stepping
the
head downwards very slowly. It also starts writing a fixed high-
frequency (preamble) panern.
A special detector circuit monitors the output from the read
head. As soon as the read head reaches the lower edge
of the
tape, the read signal disappears and the edge detector informs the
microcomputer that the edge is detected. The head is then
stepped
50 steps downwards and then again upwards until the
detector circuit once more senses the tape edge. This position is
marked as the tape Edge, and the tracks funher written are
aligned with reference
to this position.
The microprocessor will remember this position as long
as the
cartridge is insened (and power is on), and it will step the head
to the accurate track locations due to the high resolution
of the
stepping system.
Track Seeking In Read Mode
When reading, the Drive will not look for the edge of the tape.
No write operation is allowed in read mode. Instead, the
microcomputer will look for the long preamble on the fIrst track,
using the same edge detector circuit as
in write mode. The Drive
will sense the upper and lower edge
of the reference track and
then the microcomputer will calculate the correct center position
of the reference track. In this way it is able to find the actual
track locations even
if the tracks were not recorded in the correct
position.
The edge seeking (or reference signal seeking) is performed only
between BOT and LP. Nonnally, the Drive has to move the tape
backwards and forwards a few times before the head has moved
enough to detect the tape edge (or reference signal).
If a cartridge that has been wrinen in another format than the
"native" one is read -like QIC-24 format on a 'IDC 3640 or-6O
-the Drive may need several passes to determine the correct
starting-point on the tape.
Due to the number
of differences in recording and positioning in
the QIC-ll format, the Drive may in extreme cases be unable to
read these tapes. See Section 6.1.

TANDBERG DATA
~
&
2-5 Introduction
to the Drive
2.4. Drive Block Diagram with Description
All drive operations are controlled by the 68HCll
microcomputer on the Mainboard. This includes the stepping
and positioning of the head. the control of the capstan motor
speed, the sensing of the tape holes and the communication with
the Host.
Figure 2.3 below shows a block diagram of the Drive .
Micro
..... d
Motion
Processor
System
c.pstan
System
Re.d
- QIC-<l2 Protocol
CirCUit
I+-
Handler
- Dynamic RAM
Controller
-3-way OMA
Controller
Bus-
~
Bus
Drivers!
Receivers
~
64 KByIe
Buffer
~
~
Write
~
Circuit
- Tape Formatter
- Motor Servo
Control
+i
Tape Hole
~ - Sensor System
Sensor
Figure 2.3 Block diagram o/the Drive
Cepstan System
WriIe!Read
Head
....
The capstan motor is controlled by a software controlled and
monitored servo system. Pulse modulation of the motor current
is used in order to reduce power dissipation in the motor.
Head Motion System
The head is moved up and down with a double-screw ("worm-
wheel") system. controlled by a stepper motor. The micro-
computer supplies
the pulses to the stepper motor. The micro-
computer is also able to detect either the edge of the tape or the
edge of the reference signals by employing the tape edge sensor
electronics. '
'The WritelAead Head
The head has two recording channels designed for serpentine
recording.
Each channel contains a write and a read section.
When writing. the Drive runs a read-after-write check to verify
the recorded data. The head also has a full-width erase part that
erases all the tracks on the tape each time the Drive.starts writing
from Track O. .

TANDBERG DATA
2-6
Introduction to the Drive
Tape Hole Sensors
The EOT (End of Tape), the BOT (Beginning of Tape), the LP
(Load Point) and the EW (Early Waming) holes in the tape are
detected by the Mainboard microprocessor using the Tape Hole
Sensor circuit. The detection system includes a sophisticated,
synchronously clocked
hardware system to avoid malfunction
and tape run-out.
The Write Circuit
This circuit performs the actual writing on the tape. Infonnation
about
the data to be written is received from the Write
Sequencer. The write circuit adapts itself to the type of tape used
(DC300XL. DC600A or DC600XTD).
For recording, the TDC 3640 should use DC600A or DC-
600XTD tapes and the TDC 3660 should only use the
DC600XID ta or uivalent from other manufacturers.
The Read Circuit
The Read Circuit detects each flux transition from the read head
and convens it to adigital pulse. The circuit is optimized to read
weak signals. thus improving the total system error rate.
The Read Clock Generator
This circuit generates a clock signal which follows the long tenn
variations in the data signal read back from the tape. A· phase
locked loop.is used to control the generation. The circuit is
optimized for OCR encoded data.
2.5. The Formatter Functions
The Formatter comprises:
- Communication microprocessor (68HCl1)
.. Data buffer
-
Control circuits for data conversion
- DMA controller
-Host
Interface controller
The Data Buffer is designed for optimal performance in disk
back-up applications. The operation is described in detail in
Section 2.7.
The microprocessor controls both the basic and the formatter
functions in the Drive. It controls the Data buffer via the custom
designed two channel DMA controller and it controls data Read .
and Write operations. It also handles the decoding of host
commands.

TANDBERG DATA 2·7 IntrodlJction to the Drive
2.6. Interface to Host
The interface to the Host conforms with the SCSI standard,
revision 17B. Communication between the Drive and the host
system is undertaken via a 9-bit bidirectional bus and nine
bidirectional control lines.
The Drive accepts commands from the Host. The Host may read
the Drive status by asking for the transfer of special status bytes
from the Drive. See Chapter 9 for a complete list
of available
commands. During read and write operations, the data bytes are
transferred via the Host Bus. The transfer
of each data byte is
supervised by the control lines in a handshake operation to
minimize timing burden on the host controller.
For a detailed description
of the hardware and software interface
to the Host, see Chapters 8 and
9.

TANDBERG DATA
2·8 Introduction
to the Drive
This Page Intentionally Left Blank

TANDBERG DATA
3-1
Product Specifications
3. Product Specifications
This section contains a comprehensive set of specifications for
the Drive.
3.1. Mechanical Dimensions and Weight
Standard drive
mounting
Fits in 5 1/4" half-height ("slim-line") enclosure for diskette or
disk drive. Standard mounting holes for a half-height drive.
Max. dimensions
Weight
44 x 150 x218 mm (1.7.32" x 5.905" x 8.583")
1.1 kg (2.4 lbs)
See Section 4.1 for mounting details and mechanical drawings.
3.2. Power Requirements
Voltage
Current
+5V
250mA •
+12 V motor not running 100mA
+12 V motor running with tape 1.2A
••
+12 V peak value (start·up) 3.9 A
...
... ExcI. the bus termination resistor network.
...... Nominal value. Actual value depends on cartridge friction.
... Assuming cartridge meeting 3M"'! spec. for torque and
friction
Current (A)
3.7 A t-------.,
Sleepfundion
turned off
(12 Vsupplied to
analog section)
1.3 A +-""'"'7"'-'---""'f--tfttHtttffitiM~""----
1.OSA
0.0 r---1====t---------
o
Motor start ran:tp • T)'Pical.140 rns
T}pica/ cu"ent curve for + 12 Vduring motor start-up
(Cartridge:
Worst case 3MTM inside spec.)
Tme(s)

TANDBERG DATA
Voltage
variations
Ripple on
+5 V
and +12 V
Power
dissipation
Operating
Storage
Transport
Mode
Operating •
Storage
Transport
+SV±5%
+12V±10%
3-2 Product Specifications
Including ripple
Including ripple (No resaictions on the
tum-on sequence).
Maximum 200 mV Peak-to-Peak.
2.25W
IS.OOW
Motor not running.
Typical. motor running with cartridge
insened.
3.3. Environmental Specifications
The following definitions are used in this section:
The
unit is unpacked and power is turned on.
The unit is unpacked and power is turned off.
The unit is packed in original package as when ready for
shipment from factory.
3.3.1. Temperature and Relative Humidity
Temperature (OC) Rei. humidity (%)
+5 -+40 20 -80
-30 -+60 10 -90
-30 -+60 10 -90
• In operating mode these figures are limited by the media. Due to
additional heating coming from internal friction in the canridge, the
maximum surrounding temperature should not exceed 40°C in order
not to violate the maximum temperature rating for the tape canridges
which is 4SoC. Maximum Wet Bulb temperature is 26°C operating.
(See figure below and IMPORTANT-notice in Chapter O. Preface).
Relative
humidity ("!o)
80
20
·s·
30·
40 Temperature P C)
Drive temperature and humidity limits, operating

TANDBERG DATA
Operating
Operating
Storage
Transport
Test method
Mode
Operating
Storage
Transport
Topple
Storage
Shock
Transport
Shock Storage
3·3
3.3.2. Temperature Variation
Maximum 6°C per hour, non-condensing
3.3.3. Atmospheric Pressure
Product Specifications
53 -106 kpa [maximum altitude 4000 m (13000 ft)]
15 -106 kpa [maximum altitude 13000 m (40000 ft»)
15 -106 kpa [maximum altitude 13 000 m (40000 ft»
3.3.4. Vibration
EC-68-2-6
Frequency
Peak Displacement Acceleration
5
60
5
58
5
12
-
60 Hz
0.035 mm ±10 % -
-500
Hz
-
0.5 G
-
58 Hz
0.150mm±10%
-
-500
Hz
-
2.0G
-12
Hz 3.5 mm±10%
-
-500Hz -
2.0G
3.3.5. Impact and Shock
Lifted 50 mm and allowed to fall on to each of the four bottom
edges and corners. (Horizontal position see section 4.1). (lEC-
68-2-31).
Lifted 1.0 m and allowed to fal1 freely on to a hard, rigid surf"lce.
Fall sequence includes al1 6 sides and the most critical edge and
corner. (IEC-68-2-32).
392 m/s2 (40 G), Half sinewave,
11 ms duration. (JEC-68-2-27).