Quantum DLT 2500, Product Manual

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DLT2000 SCSI Interface
DLT2000/DLT2700 Cartridge Tape Subsystem 8-81
Write Buffer Full Ratio and Read Buffer Empty Ratio
These indicate how full/empty the buffer memory should be before restarting the
writing/reading of the media. The DLT2000 will set these fields to zero (unused)
because it uses an automatic, adaptive mechanism to dynamically adjust its full/empty
ratios according to the average data rates over the SCSI bus.
Write Delay Time
This indicates the maximum time that the drive will wait with a partially full buffer
before forcing the data to tape (100 ms increments). Note that the buffer full/empty
ratio, which is dynamic, can cause data to be written sooner than the Write Delay time
would indicate. The Write Delay Time defaults to 200 (C8h). This causes the buffer to
be flushed in 20 seconds. Maximum value is 6500 (1964h) and the minimum is 15 (Fh).
This represents delays from almost 11 minutes down to 1.5 seconds.
Byte 8:
DBR–set to 0 (Data buffer recovery not supported)
BIS–set to 1 (Block Identifiers Supported in media format)
RSmk–set to 0 (Setmarks not supported)
AVC–set to 0
SOCF–set to 0
RBO–set to 0
REW–set to 0 (Do not report Early Warning EOM on reads)
Gap Size
This field is not used and is set to zero.
EOD Defined
This field is set to 00h.
EEG
The Enable EOD Generation bit is set to indicate that the drive will generate an EOD.
The drive generates an EOD mark before any change of direction following a write-type
operation.
SEW and Buffer Size at Early Warning
The Synchronize at Early Warning bit is set to 1. Buffer Size at EW fields are not
supported and will be zero.
Select Data Compression Algorithm
One enables data compression; zero disables it.