[Simh] Problem with reading tape with PDP-11 SIMH

[Mark Pizzolato - Info Comm]

On May 21, 2015 12:32 PM, Alan Frisbie <frisbie at flying-disk.com> wrote:
>
> Mark,
>
> > > The difference with the simulator vs the real hardware is that,
> > > in general the TPC program may never get a chance to queue more
> > > than one I/O to the device since the first operation will likely
> > > complete BEFORE control returns to the user mode program.  This
> > > may stress the user mode program in ways which it never saw when
> > > real tape operations took many milliseconds (or seconds).
> >
> > An excellent point, which I had not considered.   I will have to
> > do some exploration in this area.
> >
> > > If this is happening, some adjustments to the behavior of the
> > > TS device can potentially be made to slow it down.  Try
> > > "sim> DEP TS TIME 5000" or change 5000 to some other large number
> > > (the default is 10).
> >
> > I will try this and let you know what happens.
>
> I tried this, and it appears to fix the problem!   At least TPC
> completes and has created a file of approximately the right size.
>
> Thank you for saving me lots of debugging time.
>
> Now the next problem:
>
> When I try to create a new SIMH "tape", I am getting a "File open
> error", but no other information.   How can I find out what the
> problem is?   Here are the commands I am issuing:
>
> sim> set ts0 format=tpc
> sim> show ts0
> TS0     not attached, write enabled, TPC format
>         unlimited capacity
> sim> attach -n ts0 newrsx11s.tpc
> File open error
> sim>

Simh does not support writing tapes in TPC format.

-Mark
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