User's Manual

DLT4000 SCSI Interface
DLT4000/DLT4500/DLT4700 Cartridge Tape Subsystem 8-47
8.4.9.1 MODE SELECT Parameter List
The MODE SELECT parameter list shown below, contains a 4-byte header, followed
by one 8-byte block descriptor.
Bit
7 6 5 4 3 2 1 0
0 Reserved
Byte 1 Media Type
2
Ignored
Buffered Mode Speed
3
Block Descriptor Length (08h)
Block Descriptor
0 Density Code
1
(MSB)
2 Number of Blocks (000000h)
3
(LSB)
4 Reserved
Byte 5
(MSB)
6 Block Length
7
(LSB)
Page Descriptors
0
PS (0)
0 Page Code
1 Additional Page Length
2 Page Defined or Vendor-Unique Parameter List
Figure 8-30 MODE SELECT Parameter List
Media Type
This field is ignored by MODE SELECT command.
Buffered Mode
The drive will implement Immediate Reporting on WRITE commands through
Buffered mode.
If the field is zero, then the drive does not report a GOOD status on WRITE
commands until the data blocks are actually written to tape. If the Buffered Mode field
is one, then the drive reports GOOD status on WRITE commands as soon as the data
block has been transferred to the buffer. This is the default configuration for the drive.
When Buffered mode is not used, the tape drive will suffer a significant degradation in
performance, and maybe capacity as well, depending on tape format, block size and