73
A simulated disc seek will fail with Status 2 Error (Drive Fault) status, and the drive’s heads will unload. Reloading
the heads will clear the drive fault. A simulated disc read or write will fail with Uncorrectable Data Error status. The
target operating system will then react to this error as though the drive had encountered a bad disc sector.
A drive’s unit number is not set explicitly. Instead, the drive unit number is derived from the simulation unit number.
For example, unit DA0 responds to disc unit select number 0. Changing the unit select switch 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 timing, drive type, protection and format status, and the ability to set
drives ready or not-ready. The command forms are:
SET DA <device-option>
SET DAn <unit-option>
5.4.1
Device Options
Device options that may be specified are:
Option
Action
ADDRESS=<n>
Set the HP-IB address; default is 0
DIAGNOSTIC
Connect the HP-IB cable to a second interface
HPIB
Connect the HP-IB cable to the drives
SC=<n>
Set the interface card select code; default is 43
DEBUG=<option>
Enable tracing
NODEBUG
Disable tracing; default
ENABLED
Enable the device; default
DISABLED
Disable the device
The
ADDRESS
option configures the interface to use the specified HP-IB address from 0-7. The interface address
is independent of the disc drive unit address and is only used for diagnostics.
Setting the
DIAGNOSTIC
option enables a second 12821A device (named DC) and simulates the installation of an
HP-IB cable between the two 12821A Disc Interface cards as required by the HP 12821A ICD Disc Interface
Diagnostic. Setting the
HPIB
option disables the second device and simulates the installation of an HP-IB cable
between the interface and the drives.
Device configuration may be displayed with the following commands:
Command
Action
SHOW DA
Display the device and unit configuration
SHOW DA CABLE
Display the HP-IB cable configuration
SHOW DA BUS
Display the bus address