Mitsubishi Electric Apricot HP DDS DRIVES User manual

HP DDS DRIVES
User Guide
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Copyright © Apricot Computers Limited 1997. All rights reserved.
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Apricot Computers Limited
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Printed in the United Kingdom

HP DDS DRIVES USER GUIDE 1
USING A HP DDS TAPE DRIVE
This document describes the HP DDS-2/3 tape drives. The
software needed to control the drives depends on your operating
environment; ask your supplier for details.
The drive has a built-in compression algorithm which can
typically double, and in some cases quadruple, tape capacity. Data
compression and decompression is transparent to the host
software.
The DDS-2 drive uses 120-metre (DDS-2) cassettes and the
DDS-3 drive uses 125-metre (DDS-3) cassettes. Both drives can
use earlier DDS format cassettes (the DDS-3 drive can read
DDS-2 cassettes, but not vice versa). The drive automatically
detects the format of the cassette when it is inserted into the drive.
It has the capability to read and write both DDS uncompressed
and DDS-DC compressed data and data cartridges.
The drive writes compressed data by default, unless it finds
uncompressed data already on the cassette. The drive can also write
uncompressed data under software control.When reading a cassette,
the DDS drives automatically distinguishes compressed and
uncompressed data and either decompresses it or passes it through
unaltered as appropriate.
Caution
Use only cassettes bearing the DDS or DDS MRS (Media
Recognition System) symbols; you cannot play audio DAT cassettes
with these drives, even on multimedia systems.
ACTIVITY
LIGHT ATTENTION
LIGHT EJECT BUTTON
CASSETTE INSERTION SLOT

2 HP DDS DRIVES USER GUIDE
N/S=not supported
Note
To gain full advantage of your DDS drive you should use matching
cassettes. That is, use DDS-3 cassettes with the DDS-3 drive. This
allows the drive to store the maximum amount of data on the tape.
Interpreting the LED indicators
There are two LED (light-emitting diode) indicators on the
drive’s front panel. The Activity (green) and Attention (amber)
LEDs show the status of the drive.
Green Amber Drive status
Flashing Off Power-on, or cassette
load/unload
Flashing rapidly Off Cassette read/write
On Off Cassette loaded
Any Flashing Media Caution signal
Any On Hardware error or high
humidity
Media Caution
A media caution signal, when the Attention LED (amber) flashes,
indicates that the tape may be becoming unreliable, although
at this point no data has been lost. First, clean the tape head
cylinder with the special cleaning cassette, then try the data
DDS-1
(without compression)
DDS-1
(with compression)
DDS-2 DDS-3
Capacity (2:1compression)
DDS-1 60m cassette 1.3 GB 2.6 GB 2.6 GB 2.6 GB
DDS-1 90m cassette 2.0 GB 4.0 GB 4.0 GB 4.0 GB
DDS-2 120m cassette N/S N/S 8.0 GB 8.0 GB
DDS-3 125m cassette N/S N/S N/S 24 GB
Transfer Rate
Max. Sustained Native 183 KB/s 183 KB/s 510 KB/s 1 MB/s

HP DDS DRIVES USER GUIDE 3
cassette again. If the warning persists, copy the data onto a new
cassette and discard the old one. The media caution signal will
clear when a new cassette is loaded or when the drive is switched
off and then back on.
A media caution signal can also indicate that a prerecorded audio
DAT cassette has been inserted by mistake.
Hardware error or high humidity
If the Drive Busy (amber) LED flashes rapidly, this indicates
either a hardware error or dew (high humidity). If this happens
soon after powering-up the computer, the drive’s diagnostic test
may have failed, in which case the drive will not operate. Request
help from your supplier or an authorized maintainer.
If the drive detects high humidity, the tape is automatically
ejected. As soon as the drive detects that the humidity is at an
acceptable level, it will return to normal operation. When high
humidity is detected, you should allow approximately 1 hour for
the drive to acclimatize before trying again.
Automatic drive operation
To prolong the life of the tape and the drive mechanism, the
drive “relaxes” during periods of inactivity (no read or write
operations):
•After 30 seconds, the capstan and pinch roller are released
and tape tension is removed.
•After 90 seconds, the tape is pulled away from the head
cylinder, and the cylinder stops rotating.
Inserting a cassette
Insert the cassette into the slot with the triangular arrowhead
on the cassette uppermost, and pointing towards the drive. As
the tape is inserted, the drive takes it and automatically loads it

4 HP DDS DRIVES USER GUIDE
into the drive mechanism. A load sequence checks ambient
humidity, the tape format and data integrity. Unless the tape is
blank the tape log, which contains a history of usage of the tape,
is read into the drive’s memory.
The drive will automatically format a blank tape when data is
first written to it. Remember to allow time for the formatting
process when you use a new tape.
Removing a cassette
Before attempting to remove a cassette, ensure that the drive is
not currently in use (the amber Drive Busy indicator must be
unlit).
Press the EJECT button on the front of the drive (depending on
your operating environment, the EJECT button may be disabled
while the drive is in use). If the tape is write-enabled, a copy of
the tape log, held in the drive’s memory, is written back to tape.
The drive rewinds to the beginning of the tape, unthreads it,
and ejects the cassette. Several seconds may pass between the
button being pressed and the cassette being ejected, so be careful
not to turn off the computer before the operation is completed.
Write-protecting a cassette
A cassette can be write-protected by sliding the white tab on the
cassette so that the recess is revealed. In this position, data can
be read from the tape but not written to it.
The tape log, which includes a record of data integrity failures,
cannot be updated while the cassette is write-protected. It follows
that the tape log becomes inaccurate if a cassette is used while
write-protected, and the media warning LED status cannot be
relied upon to determine if the cassette needs to be copied and
replaced.

HP DDS DRIVES USER GUIDE 5
Keep your cassettes well away from magnetic objects, and
equipment that generates magnetic fields. Avoid extremes of
temperature and exposure to direct sunlight; otherwise, the data
recorded on the tape may become corrupted
Cleaning the drive
The read/write heads in the tape drive are protected during
normal operation by a built-in cleaning roller. In addition, a
special cleaning cassette, HP 92283K is available from your
supplier. This cassette should be used:
•After the first 4 hours of tape movement of a new cassette.
•Every 25 operating hours.
•When the Media Caution signal is displayed.
When you insert the cleaning cassette, the drive recognises it as
a cleaning cassette, runs it for about 30 seconds, then ejects it
automatically. Each time the cleaning cassette is used the tape
advances over an unused portion of the tape. If the drive ejects
the cleaning cassette immediately after you insert it, this means
that the entire tape has been used and a new cleaning cassette is
required. You cannot rewind a cleaning cassette.
Caution
Do not attempt to use an ordinary audio DAT cleaning cassette.
The drive will be unable to recognise it as a cleaning cassette.
WRITE
ENABLED WRITE
PROTECT

6 HP DDS DRIVES USER GUIDE
Setting the SCSI ID
The SCSI ID is set using jumpers on the set of pins beside the
SCSI connector at the rear of the drive, as shown below:
SCSI Jumper Pins
The three significant bits in the ID give a range of 0 through 7
as follows:
SCSI ID Bit 2 Bit1 Bit0
0000
1001
2010
3011
4100
5101
6110
7111
1=shorted
0=open
The drive reads the SCSI ID at power-up and during self-test.
Data Compression Control
Data compression can be controlled through the jumper pin
shown above.The pin is only monitored at power-on, and controls
whether data compression is enabled by default. Any subsequent
change to the pin are ignored.
SCSI connector
Power connector
Term power
Bit 2
Bit 1
Bit 0
Compression on/off,
using a control cable

HP DDS DRIVES USER GUIDE 7
Pin State Effect
Unconnected This is the default. Data compression
is controlled by configuration switches
1 and 2 (on the underside of the drive)
and through the SCSI MODE
SELECT command.
Connected to 0V Data compression is disabled. The
setting of configuration switch 1 is
ignored. Switch 2 is valid. However,
data compression can still be controlled
through MODE SELECT. Note that
when reading, the drive will always
decompress compressed data.
It follows from this that if you wish to
use this pin, you should set
configuration switch 1 on the
underside of the drive to ON.
Terminator Power
The drive will provide termination power for the SCSI
termination resistors if a jumper is set across the two pins marked
“Term power” as shown in the diagram.
Configuration switches
There is a set of configuration switches on the underside of the
drive, shown overleaf:
With the drive switched off, use the information below to select
the correct configuration for your system.
ON
12345678
On On Off On On On On On

8 HP DDS DRIVES USER GUIDE
Note
For the drive to operate correctly, appropriate drivers and application
software must be loaded on the host computer.
Data compression
Switches 1 and 2 are normally a used to configure the way in
which data compression is set for the drive. The following table
shows the available options:
Switch 1 Switch 2 Meaning
On On Compression enabled at power-
on with host control
On Off Compression enabled at power-
on no host control.
Off On Compression disabled at power-
on.The host is allowed to control
compression.
Off Off Compression disabled at power-
on no host control.
When switch 1 is on, data written to the tape will be compressed
without the knowledge of the host.
Media Recognition System (MRS)
Switch 3 is used to configure the drive to respond to DDS Media
Recognition System tapes:
Switch 3 Meaning
On The Media Recognition System is disabled. All
DDS tapes are treated the same, whether they
possess the Media Recognition stripes or not.
Off The Media Recognition System is active. This
is the default setting. Non Media Recognition
System tapes are treated as if they are write-
protected.

HP DDS DRIVES USER GUIDE 9
Switches 4 to 8
Switches 4 to 8 are used to specify connectivity and functionality
according to host or customer requirements. The default settings
for all switches is on.

10 HP DDS DRIVES USER GUIDE
Specification of HP DDS tape drives
Performance specifications apply when using data compression.
Power specifications are measured at the tape drive power
connector and are nominal values.
The compression ratio and transfer rate achievable in any
particular case depend on the characteristics of the data being
compressed.
Nominal capacities 60-metre cassette 1.3 Gbyte (1:1 base)
(DDS) 2.6 Gbyte (2:1 typical)
5.2 Gbyte (4:1 max1)
90-metre cassette 2.0 Gbyte (1:1 base)
(DDS) 4.0 Gbyte (2:1 typical)
8.0 Gbyte (4:1 max1)
120-metre cassette 4.0 Gbyte (1:1 base)
(DDS-2) 8.0 Gbyte (2:1 typical)
16.0 Gbyte (4:1 max1)
125-metre cassette 12.0 Gbyte (1:1 base)
(DDS-3) 24.0 Gbyte (2:1 typical)
Transfer rates DDS 366 Kbyte/s (1:1 base)
732 Kbyte/s (2:1 typical)
1464 Kbyte/s (4:1 max1)
DDS-2 400 Kbyte/s (1:1 base)
800 Kbyte/s (2:1 typical)
1608 Kbyte/s (4:1 max1)
DDS-3 1000 Kbyte/s (1:1 base)
2000 Kbyte/s (2:1 typical)
1Nominal maximum only; can be exceeded for highly-compressible data.
Note DDS-3 standard is only on the DDS-3 drive.
Unrecoverable errors Less than 1 in 1015 data bits
Recording format ANSI/ECMA (DDS-DC, DDS-2/3)
Power specification Voltage +12 Vdc ± 10%
+5 Vdc ± 5%
Ripple +12 V: <=150 mVp-p
+5 V: <= 150 mVp-p
Current (operational) 0.4 A @ +12 Vdc, 0.8 A @ +5 Vdc
Current (peak) 0.9 A @ +12 Vdc, 1 A @ +5 Vdc

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