User's Guide

Commands: Read (08h) Page 109
For example, assume the following:
• The drive is currently positioned before block N.
• Block N + 1 contains 512 bytes.
The host issues a READ command with a CDB Transfer Length of 514, indicating
514 bytes of data to be read. The drive transfers the first 512 bytes of block N; then
stops because of an Incorrect Length error. The logical position after the error is
after byte 512 of block N.
If the SILI bit is set (1), the drive does not report a Check Condition (caused by
Incorrect Length error).
If the SILI bit is reset (0), the drive reports a Check Condition, and the residual is set
to 2 (CDB Transfer Length = 514).
In the above example, if the block size of block N is 514 bytes and a READ
command specifies a Transfer Length of 512 bytes, the drive transfers the first 512
bytes of block N; then skips the last two bytes to position itself at the end of byte 514
of block N. The residual is set to -2. Because the actual block length exceeds the
CDB Transfer Length, the drive unconditionally reports Check Condition. In this
case, the residual is set to -2.
Completion Status
The Completion Status for the READ command is shown in the following table.
Code Message Description
00h Good
Status
• The drive is ready to perform any appropriate command.
• The drive remains in any previously set mode.
• The tape is positioned on the EOT side of the last block read.
02h Check
Condition
Extended Sense Byte 02h
Code Message Description
02h Not Ready No cartridge is inserted in the drive.
03h Media Error Unrecoverable data error encountered.
04h Hardware Error Drive hardware failure detected.
05h Illegal Request The CDB contains an invalid bit.
06h Unit
• Cartridge was changed prior to accepting
Attention this command
• The drive was reset prior to this command.
08h Blank Check The drive encountered EOD.