Sunday, December 20, 2015

Load deck cleanup and a bit of work on 1053 restoration


Took another test pass on the spare but wrong sized ribbon color tape perfecting the technique I will use to repair the correct sized broken tape. I want to take another pass at it tomorrow as I have just the one correct tape and can't afford to ruin it.


I worked out a modification for the assem1130 program that Brian Knittel wrote as part of the IBM 1130 simulator. This adds a parameter (-k) that is used with system phases, allowing me to stick on a type 1 header via a SBRK card as the new front of the source deck. SBRK also will pick off the first five characters of the sequence field and use it for the output deck, resetting the three digit sequence numbers for each phase.

Then, the output decks look more like the real card decks that come from IBM. I could add further nuances if needed - for example if the increment per card for the sequence field is not always one but sometimes by tens.

I now have the phase decks for a V13 update and for a full initial load of V13. I finalized the decks and tested them on the simulator. There are some issues which I am chasing down.


  1. Did someone say that IBM used a cross-assembler for 1130 code that ran on a System/360? Is this available anywhere? Probably not relevant to what you're doing, but still interesting.

  2. Hi Pete

    Yes, that is the supposition of Brian Knittel, who initially recreated DMS R2 for users of his simulator. When he assembled the source on an 1130, he found that certain directives are missing such as SBRK and some values are generated with differing values.

    Rather than finding the 360 cross assembler, he wrote his own assembler that runs under DOS/Windows and yields object decks -- card images - in 1130 simulator format. It is in the Utils folder of the downloaded files for the simulator from