Mode Block Descriptor - Seagate STT20000A Product Manual

ATAPI Interface

Mode Block Descriptor

STT20000A Product Manual
The only supported Buffered Mode (bits 6-4 of byte 2) is 001, indicating that write
operations are buffered. Only the Speed Selection field can be changed.
The following table defines the tape speeds supported with QIC-3095 tapes.
Speed Tape Speed
0000b Automatic
0001b 46 ips
0010b 69 ips
0011b 92 ips
The Block Descriptor is returned to the MODE SENSE command unless the DBD bit
in the command packet is set to one. If the Block Descriptor is not sent, the Block
Descriptor Length field (in the Mode Parameter Header) is 0.
Byte Description
4 Density Code
5-7 Number of Blocks
8 Reserved
9-11 Block Length
The Number of Blocks is 0, indicating that all blocks in the media match this
descriptor, (the blocks are fixed 512 byte blocks).
None of the Block Descriptor parameters may be changed (Block Length is fixed).
Transfer Rate
Automatic
489 Kbytes/sec
733 Kbytes/sec
1,000 Kbytes/sec
Value Meaning
NN Current Density
000000h Zero
00h —
000200h Always 512 byte blocks
Chapter 5
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