Chapter 5 ATAPI Interface
Page 52 Seagate Travan 40 Product Manual
cause of the error. While writing, the drive will revert to Unbuffered Mode when
Logical Early Warning (LEW) is reached. A REWIND issued at this point will cause
the drive to rewind to BOT and return to Buffered Mode.
Speed Code: The values of speed codes are given in the table below. The Speed
Code may be set explicitly by MODE SELECT command, or implicitly when AVC
(Auto-Throttle) is set to 1 (bit 4, byte 8 of page code 10h). If AVC is set to 1, MODE
SENSE will report the actual speed selected to optimize data throughput.
Code Meaning Tape Speed Transfer Rate
0h Use default speed. 92 ips 2.0 MBps
1h Use lowest tape speed. 56 ips 1.2 MBps
2h-Fh Use highest tape speed. 92 ips 2.0 MBps
Block Descriptor Length: Specifies the number of bytes in the Block Descriptor.
This value is 08.
Block Descriptor
Data Bits
Byte 7 6 5 4 3 2 1 0 Hex
0 Density Code 45h
1
2
3
MSB
Number of Blocks
LSB
00
00
00
4 0 0 0 0 0 0 0 0 00
5
6
7
MSB
Block Length
LSB
XX
XX
XX
Density Code: This byte identifies the bit density and format of the media used by
the drive. The value returned by this field is determined by the last MODE SELECT
command, or is the default value based on the cartridge type and/or previously
recorded density following a power-up reset. See MODE SELECT for a table of valid
Density Codes.
Number of Blocks: This field must be 0.
Block Length: This field specifies the block length and mode. If this field is 00h, the
drive operates in variable length block mode. If this field is non-0, the drive operates
in fixed length block mode and the logical block length is equal to the value of this
field. The STT3401A default block length is 512 bytes.
Page Code 01h is used to specify target Error Recovery and Reporting parameters.