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Attaching a disc image file to a unit simulates inserting a disc pack into a drive:
ATTACH {-R} DQCn <image-filename>
Adding the
–R
(read-only) switch prevents writing to the disc image.
If the host operating system returns an error when reading or writing a disc image file, the simulator will report the
error to the simulation console, e.g.:
HP 2100 simulator DQ disc I/O error: No space left on device
...and the simulation will stop with an
I/O Error
message. No error recovery is attempted.
A drive’s unit number is not set explicitly. Instead, the drive unit number is derived from the simulation unit number.
For example, unit DQC0 responds to drive select number 0. Changing the drive select jumpers on a mounted drive
is simulated by detaching and reattaching the disc image file to the corresponding simulation unit.
Device and unit options include configuring the protection and drive-ready status. The command forms are:
SET DQC <device-option>
SET DQCn <unit-option>
Device options that may be specified are:
Option
Action
SC=<n>
Set the interface card select codes; default is 24/25
ENABLED
Enable the device; default
DISABLED
Disable the device
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 command:
Command
Action
SHOW DQC
Display the device and unit configuration
Unit options that may be specified for 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
Prohibit writing to the drive
UNPROTECT
Permit writing to the drive; 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, and the
UNPROTECT
option permits writing. These options
have no hardware analog; writing is always permitted on the 2883A. Also, the drive Format switch is not supported;
drive address protection is permanently overridden.
