User's Guide

Chapter 3 Emulated DLT7000 SCSI Commands
Mode Select (6 /10) (15h / 55h)
Quantum DX-Series Software Interface Guide 189
Table 144 Data
Compression Page
Descriptor - Field
Descriptions
.
Field Name Description
PS The Page Code identifies the type of MODE
SELECT page being transferred. A value of 0Fh
identifies this as the Data Compression page.
Page Length The Page Length field indicates the number of
bytes in the Data Compression page that follow
this byte. The valid value for this byte is 0Eh.
DCE Data Compression Enable. This bit specifies
whether the tape drive should enable or disable
data compression. When set to 1, the drive starts
in compressed format.
DDE Data Decompression Enable. Must be set to 1.
When the tape drive reads compressed data
from tape, it automatically decompresses the
data before sending it to the initiator. Data
compression must always be enabled.
RED Report Exception on Decompression. The tape
drive does not report exceptions on
decompression (boundaries between
compressed and uncompressed data). The RED
field must be 00h.