Verify - HP 9895A Service Manual

A-36 HP 9895A Disc Memory Command Set
Verify
Type:
Purpose:
Description:
HP-IB Sequence:
Status:
ATN
IPOlADDRSI
Primary
Listen
Disc read.
The Verify command is a read with reduced margins which
does not transfer data to the HP-IB. This is useful for per-
forming a surface analysis of the disc or checking the integ-
rity of the data on the disc.
As with other read commands, parallel poll is disabled, the
availability of the unit is checked, and the target sector is
sought. Starting with the target sector, consecutive sectors
are read using reduced margins until any of the following
occurs:
1. Unable to begin verify operation,
2. Sector count given in the command expires,
3.
A seek or read error occurs,
4. A sector marked defective is detected,
5. The end of the disc is reached.
Parallel poll response is re-enabled upon completion of the
verify. If an error was detected, the target address points to
the sector in which the error occurred. Otherwise, the
target address points to the sector following the last sector
read.
Verify Request
ATN
p
P1101000 P
I
Secondary
I
D
00111
Opcode
I
EOI ATN
Sector Count
No errors.
Sl
-0
Stat 2 - Unchanged
DSJ -0
Verify error.
Sl - Error
p
~
I
POl 11111
I
Unllsten
uuuul
Unit
Stat 2 - Bits A, E and C set, if appropriate.
DSJ -1