83
If the host operating system returns an error when reading or writing a tape image file, the simulator will report the
error to the simulation console, e.g.:
HP 2100: Magtape library I/O error: No space left on device
If this or another tape library error occurs, e.g., due to an illegal or damaged tape format, the simulator stops with
an appropriate error message. Resuming the simulation will fail the tape operation with Tape Error status. The
target operating system will then react to this error as though the drive had encountered a bad tape block
(CRCC/LRCC or STE/MTE error).
A drive’s unit number is not set explicitly. Instead, the drive unit number is derived from the simulation unit number.
For example, unit MSC0 responds to tape unit select number 0. Pressing a different unit select button on a
mounted drive is equivalent to detaching and reattaching the tape image file to the corresponding simulation unit.
Pressing the
OFF
button is equivalent to setting the drive offline.
Device and unit options include configuring the drive type and timing, tape reel size, tape image format, and the
ability to set drives offline or online. The command forms are:
SET MSC <device-option>
SET MSCn <unit-option>
6.2.1
Device Options
The device options that may be specified are:
Option
Action
13181
Use the 13181B interface and 7970B drives; default
13183
Use the 13183B interface and 7970E drives
FASTTIME
Use optimized timing; default
REALTIME
Use realistic timing
SC=<n>
Set the interface card select codes; defaults are 30/31
DEBUG=<option>
Enable tracing
NODEBUG
Disable tracing; default
ENABLED
Enable the device; default
DISABLED
Disable the device
The
13181
and
13183
options set the interface type and, by implication, the tape drive type.
When realistic timing is enabled, the simulation accurately models the tape movement times (in machine
instructions). For example, rewinding takes longer if the tape is positioned farther from the load point. Realistic
timing is necessary to pass the magnetic tape diagnostic timing tests.
Optimized timing reduces the timing to the minimum necessary to operate correctly; this is much faster than the
real tape drive would operate. In addition, enabling optimized timing also omits the initial erase gap normally
written after the BOT marker and the erase gap written by the Gap and File Mark (GFM), which is executed as a
Write File Mark (WFM) command. This does not affect gaps written with the Write Gap command.
The delay times used by the simulator in
FASTTIME
mode may be set via the register interface. The values may
be adjusted as necessary to work around any HP software problems that are triggered by the unusually rapid tape
operation. Resetting the device with the
RESET –P
(power-on reset) command restores the original optimized
times.