Tuesday, December 15, 2015

Initial system load of DMS R2 V11 and update process to V12 working properly

I am off to Lima, Peru for a few days on my last trip on the horizon. Once I am back this weekend I can get fully back to the 1130 system.


I made some improvements and retested my initial load deck for DMS R2 V11 - it now appeared to work perfectly. I ran the sample programs and got proper results from Assembler and Fortran, but RPG looped and COBOL apparently didn't load at all during my load procedure.

The reason for the problem with COBOL is that IBM inverted the logic for the MODE card for COBOL versus the other compilers. If you are loading RPG, Assembler or FORTRAN, you leave the assigned column of the MODE card blank. A letter A, R or F in the appropriate column means that the compiler will NOT be loaded. COBOL, on the other hand, uses a blank in its column to mean that the compiler is skipped. I had to add in an explicit C in column 15 of the MODE card to have the loader process the COBOL phases.

The COBOL compiler is now active and I ran the sample job, which compiled fine but looped after printing the first line of output. Interestingly, that was the same symptom for the RPG sample job. Another person who had donated an RPG formatted disk image to the IBM1130.org site for use with the simulator had some advice - that some simulator parameters had to be adjusted to reduce the CPU load of the card reader emulation in order to have the 1132 printer work properly.

The looping jobs had turned on the FORMS CHECK light, which claimed that the output file was not hooked to the printer, but I believe this was a symptom of the printer emulation failing. The changed parameters for the simulator allowed my RPG job to work properly, but the COBOL sample program still fails with those values.

Since the COBOL failure mode is the same as the RPG one, a spurious FORMS CHECK lamp on the simulator, with only the heading line having been printed, I will chalk this up to a simulator flaw. If I have time, I will try some other values for the simulator parameters to see if that allows the job to complete.

There are some limitations in the 1130 simulator, excellent as it is generally, such as this printer flaw and the modeling of the card reader/punches, which is not faithful to the real peripherals and thus lacks the ability to set the last card indicator reliably.

I found a site offering modified source code to match all the outstanding PTFs for DMS R2 V12 thus this would have been a V13 if IBM had released it that way. I am considering creating a V13 update deck so that users can apply those fixes and have a 'R2 V13' system. I downloaded all the source code which I can assemble and form up into a reload deck.

First, however, was the test for an update of a V11 cartridge to V12 using my decks. That ran well and produced a working cartridge with DMS R2 V12 on it. I also arranged the decks so that I could run UCART to build a distribution disk for the V12 update, as it was sent to the owner of my 1130 system.


I found a problem where my neutral line on the buildings plug was not properly torqued down, resulting in sporadic loss of that line. It affected the 120V loads in the shed. After redoing the plug my power is solid, so that I can plug the building into the outdoor outlet on the side of my house and run the systems in the shed. 

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