Sunday, December 20, 2015

Work on 1130 simulator tools for system load deck


I noticed that the assembled output of a module has a garbage header card at the beginning of the output, whereas the SBRK commands produce the proper type 1 card for all the remaining phases in the assembled file. This tells me that something is missing in the process that Brian devised, which should have included a default header value for the first phase in each assembled module.

I will look over the source for the assem1130 program to see if I can figure out what has to happen to produce the right type 1 card at the start of the binary output deck. Right now, it assembles this as a relocatable or absolute object deck, with a type card that is inappropriate to system phases.

It appears that I should add an SBRK card to the source deck to inject the first type 1 card text. This produces the same invalid type 1 and then the SBRK version so I need to do tweaking to the program itself not just the source decks.

Initially I could just replace the mangled type 1 record with the proper header text to get usable files. I also note that the output of assembling the files sometimes produces different deck prefixes in columns 73 and onward compared to the card decks produced on a real 1130. This suggests that the assem1130 program should have some way to control the value in the sequencing field. More study needed for this.

Note that this is a problem with the source based recovery done by Brian Knittel and used with the 1130 simulator. Since I have IBM distributed decks for R2 V11 and R2 V12, I can ignore the problem for those releases, but when trying to assemble the "PTF" decks for the 'R2 V13" release, the header cards and sequencing is not faithful to the existing decks. I could create a utility to resequence decks if there is not a clean simple way to adapt the assem1130 program.

I made progress during my trip to Lima but didn't finish. I arrived back home Saturday and spent my barely conscious hours with family.

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