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Device options that may be specified are:
Option
Action
12557A
Use the 12557A interface and 2870A drives
13210A
Use the 13210A interface and 7900A drives; default
SC=<n>
Set the interface card select codes; default is 22/23
ENABLED
Enable the device; default
DISABLED
Disable the device
The
12557A
and
13210A
options set the interface type and, by implication, the disc drive type.
When entering the
SC
option, specify the lower select code with either device name; the higher select code will be
set automatically, and the cards will be assigned in the correct order.
Device configuration may be displayed with the following commands:
Command
Action
SHOW DPC
Display the device and unit configuration
SHOW DPC TYPE
Display the interface type
Unit options that may be specified for the individual disc drives are:
Option
Action
UNLOAD
Set the drive’s Run/Stop switch to
Stop
; default when detached
LOAD
Set the drive’s Run/Stop switch to
Run
; default when attached
PROTECT
Set the drive’s Data Protect switches to
On
UNPROTECT
Set the drive’s Data Protect switches to
Off
; default
ENABLED
Enable the unit; default
DISABLED
Disable the unit
The
UNLOAD
and
LOAD
options unload and load the drive's heads from the disc pack, setting the drive not-ready
and ready, respectively.
UNLOAD
provides a convenient method of setting a drive "down" without detaching the
associated disc image file.
The
PROTECT
option prevents writing to the disc. It is the hardware equivalent of setting the Upper and Lower
Data Protect switches to the
On
position. The
UNPROTECT
option permits writing and is equivalent to setting the
switches to
Off
. Separate protection for the upper and lower platters of the 7900 drive is not supported. Also, the
drive Protect/Override switch is not supported; drive protection is permanently overridden.
The interface supports the
BOOT
command to load a disc boot extension. The
BOOT {–R} DPC
command is
equivalent in hardware to setting the S register to select and configure the HP 12992F boot loader ROM, pressing
the IBL button to copy the ROM into memory, and pressing the PRESET and RUN buttons to begin execution. The
S register is set as follows:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
1
0
0
DPD select code
unchanged
0
0
If the
–R
switch is specified, bit 0 is set to 1 to boot from the removable platter. If
–R
is not specified, then bit 0 is
set to 0 to boot from the fixed platter.
Bits 5-3 of the existing S-register value are retained when the
BOOT
command is executed and are available to the
boot extension program.