Quantum LTO 4, Руководство пользователя

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SCSI Commands: 28BREAD Page 127
3.16.2.9 Variable Mode Residual Data
When the Fixed bit is zero, the residual data is always set to the CDB Transfer
Length.
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 one, the drive does not report a Check Condition (caused by
Incorrect Length error).
If the SILI bit is zero, 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.
3.16.3 READ Completion Status
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 EOM side of the last block read.
02h Check
Condition Use the REQUEST SENSE command to retrieve status information. Possible
Sense Keys are:
Code Message Description
02h Not Ready No cartridge is in the drive.
03h Media Error Unrecoverable data error encountered.
04h Hardware Error Parity error on the SCSI bus or drive hardware
failure.
05h Illegal Request The Command Descriptor Block is invalid.
06h Unit Attention The cartridge was changed, or the drive was
reset prior to this command.
07h Data Protect Encrypted data found while in Disabled
Decryption mode; or unencrypted data found
while in Decrypt mode; or valid decryption key
unavailable. The logical position is at the BOP of
the failing block.
08h Blank Check The drive encountered EOD.