152 Commands
VERIFY 13h
VERIFY verifies one or more blocks beginning with the next block on the tape.
The verification is media verification only. It reads data from the tape as it
would for a read but then immediately discards it. No data is transferred
between the host and drive.
The command is identical to the
READ command in most respects. The pre-
execution checks are identical. Sense data reporting on errors/exceptions is
identical. The only differences are:
■ No data phases occur during verification.
■ The Verify command has no SILI bit. When an illegal length record is
encountered,
Verify behaves like READ with the SILI bit clear.
Note V
erify will not complete until all data has been read. It does
support the ANSI “byte compare” or “Immed” options (see the
ANSI SCSI specification).
Pre-Execution Checks:
Command Descriptor Block:
CDB Fields:
Illegal Field Fixed Bit Reservation Deferred Error
Unit Attention Media Access Diagnostic Status
7 6 5 4 3 2 1 0
0
Operation Code (13h)
1
Reserved (0) Immed(0) BCmp(0) Fixed
2
(MSB)
Verification Length
3
4
(LSB)
5
Control
Immed 0 The Immediate Reporting option is not supported, so this bit must be 0.
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