- Force the detection point of a tape structure error to be the logical EOM
on the tape.
- Enable SIGINT abort of a possibly long running validation scan
- Add -L detail record structure option at ATTACH time
- Add extra garbage at end of generated test data files
- Different systems used tape marks in different ways that are now
tolerated (multiple successive ones located on different parts of
the tape, etc.)
- Always validate beginning and end of record length indicators to avoid
moving into invalidly structured tape data
With this update, the erase gap operation has been split out of
"sim_tape_wrgap" into a separate, internal "tape_erase_fwd" routine that
is called from "sim_tape_wrgap" as well as from the new "sim_tape_errecf"
routine. There's a corresponding internal "tape_erase_rev" that's called
from the new "sim_tape_errecr" routine.
I've shimmed "sim_tape_rdlntf" and "sim_tape_rdlntr" to move the tape
context and debug stuff out of the routines that I'm maintaining. This
will allow me to replace those functions in their entirety with the
corresponding functions in my development sources for future updates.
It also allows me to keep Bob's version in sync. As my routines are static
and only called once from the shims, compilers should optimize away
the function calls and instead inline the code, so there'd be no extra call
overhead.
I'd also like to keep "tape_erase_fwd" and "tape_erase_rev" untouched for
the same reason. If you wish to add debug calls to "sim_tape_errecf" and
"sim_tape_errecr", that's fine.
Asynchronous clocks are now built for all simulators which are built with
SIM_ASYNCH_IO defined. The default behavior has asynchronous clocks
disabled since this is still experimental, but it can be enabled with
SET TIMER ASYNC.
Catchup clock ticks are now available, but since they're experimental,
they aren't enabled by default. Catchup ticks are only available if the
simulators clock device calls sim_rtcn_tick_ack to acknowledge processing
of clock ticks. The VAX simulators have been modified to leverage this.
Catchup clock ticks can be enabled with SET TIMER CATCHUP
Additionally, an idle threshold is provided which can be used to
influence when clock calibration may be suppressed. The default is not
to suppress calibration activities.
The various timer behaviors are visible with the SHOW TIMER command.
The state of the operating timer facilities is visible with: SHOW CLOCK
Timer events which are queued are visible with the SHOW QUEUE command.
Reworked all priority adjustment code to leverage a new
sim_os_set_thread_priority API which is coded to use pthreads or OS
priority adjustment APIs as necessary.
These changes facilitate more robust parameter type checking and helps
to identify unexpected coding errors.
Most simulators can now also be compiled with a C++ compiler without
warnings.
Additionally, these changes have also been configured to facilitate easier
backporting of simulator and device simulation modules to run under the
simh v3.9+ SCP framework.
If a TPC format tape image has garbage at the end of the image, but the
image contains multiple successive tape marks, then assume that logical
End Of Tape is immediately after the last successive tape marks.
OBSERVATION: Calling "sim_tape_rdrecf" to read a tape record sometimes
returns MTSE_EOM and sets the "position not updated" (PNU) flag, even when
an erase gap precedes the EOM. The correct response should be to return
MTSE_RUNAWAY to indicate that spacing over a gap did not end with a data
record or tape mark. Moreover, PNU should not be set, as the position has
been updated.
CAUSE: The routine attempts to handle this case by returning MTSE_RUNAWAY
if the EOF was detected while reading a buffer of gap markers. However, if
a buffer read ends immediately before an EOM marker or the physical EOF,
the next read attempt will return a zero buffer length. The routine
misinterprets this to mean that no gap was present and returns MTSE_EOM and
sets the PNU flag.
RESOLUTION: Modify "sim_tape_rdlntf" (sim_tape.c) to determine whether the
EOM marker or physical EOF was seen on the first or a subsequent buffer
read, and to return MTSE_EOM with PNU or MTSE_RUNAWAY without PNU,
respectively.
