SimH IBM1130 GUI appears broken

JAMES FEHLINGER jfehlinger at
Wed May 3 22:31:30 CDT 2017

In case anybody here is interested, I've discovered a
satisfactory (to me, at least) resolution to this problem.

I downloaded Carl Claunch's DMS disk (dms32k25011403.dsk)

This version of DMS is built for a 1403 printer and
a 2501 card reader, whereas the DMS that comes with the software
kit from is built for an 1132 printer
and a 1442 reader/punch (and you do get 32k of memory
with Carl's disk instead of 16k).

So you have to change any initial SimH command files to
reflect the new configuration; e.g. with "guijob" you
need to add:

set cpu 32k
set prt 1403
set cr 2501

Also, any sample Fortran programs need to have their IOCS
control records changed.  I.e., "1132 PRINTER" becomes
"1043 PRINTER" and "CARD" becomes "2501 READER", as per the
table on p. 41 of the Reference Guide document from
Additionally, the Fortran logical unit numbers in your
Fortran programs need to change as per the table on p. 41:
"READ(2, ...)" becomes "READ(8, ...)" and
"WRITE(3, ...)" becomes "WRITE(5, ...)".

Using this DMS disk (and with the appropriate changes to configuration
files and Fortran decks), the latest SimH Win32 build (from May 2, 2017)
works fine -- the simulator goes into Wait and allows access to the
GUI following a boot of DMS and after a job finishes executing.

The 2250 Graphics Display Unit and plotter sample programs from also work, with appropriate changes to their config

You still can't use CPU throttling (to slow down the register light show)
unless you're willing to use the unrealistic "IMM STOP", load card reader,
"boot dsk" sequence to run a program.

I also haven't been able to get Carl Claunch's Lunar Lander
program (there's a download link in an IBM1130 Google group post)
to get past its initial instructions (on the console) and
first couple of prompts for input.  Seems to have something to do
with not reading properly from the keyboard.  But that's another story.  ;->

More information about the cctech mailing list