User's Manual

DLT2000 SCSI Interface
DLT2000/DLT2700 Cartridge Tape Subsystem 8-83
DCE (Data Compression Enable)
The Data Compression Enable bit indicates whether data compression is enabled. The
value returned for this bit depends on the current write density of the DLT2000 as
follows:
0 - Data compression is disabled.
1 - Data compression is enabled.
DCC (Data Compression Capable)
The Data Compression Capable bit indicates whether the device supports data
compression as follows:
0 - The device does not support data compression
1 - The device supports data compression and will process any data sent to it by the
initiator according to the setting of the DCE bit (byte 02, bit 7)
The DLT2000 supports data compression in its native mode, so the value returned for
this bit is 1.
DDE (Data Decompression Enable)
The Data Decompression Enable bit indicates whether data decompression is enabled
or disabled as follows:
0 - Data decompression is disabled.
1 - Data decompression is enabled.
When the DLT2000 reads compressed data from tape, it automatically decompresses
the data before sending it to the initiator. Therefore, the value returned for this bit is
always 1 (data decompression enabled).
RED (Report Exception on Decompression)
The DLT2000 does not report exceptions on decompression (boundaries between
compressed and uncompressed data). The value returned for the RED field is 00h.
Compression Algorithm
The value returned for the Compression Algorithm field is 10h. This indicates Lempel-
Ziv (DLZ) high efficiency data compression algorithm.
Decompression Algorithm
The value returned for the Decompression Algorithm field is 10h. This indicates
Lempel-Ziv (DLZ) high efficiency data decompression algorithm. If EEROM parameter
EnaRepDCcomp is set, zero value will be reported if the last block read is not
decompressed.