Friday, November 20, 2015

Utility to recreate phase decks from system cartridge working properly


I continued testing the code as I flew home, getting it nearly ready to use. By the early afternoon I had a clean run through the first sector of the SLET - phases 01 to 98 - but found a bug in my code to skip the five device entries from 99 to 9D.  Once fixed, the utility appeared to punch out all the decks properly, with their header cards and all separated by the 9s cards the way that UCART punches the decks.

I am still missing the text for 31 of the header cards, since I didn't have those phases in my card trays. I will check a few other sources to see if I can capture the missing header cards. Since they are in straight hollerith code, it should be easy to snap a picture of a card to extract the text.

I need a quick small utility to split out the decks into separate files, so that they can be manipulated and used in an initial system load. My first major proof point of this will be to build a scratch disk cartridge on the 1130 simulator and use my deck of cards from the utility to load the disk. Then, I can compare them sector for sector with the cartridge I used as the input to my utility. They should match exactly.

If they do match, then I can run this on the real 1130 with my disk cartridges to capture the accurate object code shipped from IBM, The disk images we have online were recreated from source tapes and listings in a herculean effort by Brian Knittel but may have undiscovered differences due to typos or other transcription errors. This process will validate the total correctness of the simulator disk images.

The major purpose is to build the full system initialization object decks from my systems, including compilers like RPG, Fortran and Cobol, so that I can walk through the steps of system building and maintenance exactly as would have occurred decades ago with real machines and distribution cartridges.


The Computer History Museum is receiving a donation of an application program that handles garment designs and plots output on the 1627, but the donor would like a machine readable copy. The deck of cards was shipped to me so that I could read them with my documation card reader and convert them to the IBM 1130 simulator format. The deck is roughly one box of cards, about 2000 punched cards.

Since columns 73 to 80 are sequencing and identification, there are a maximum of 72 characters per card. This deck has just over 140KB of characters, but realistically probably closer to 60K since many cards are much shorter than 72 columns, with spaces taking up all the remaining columns. 

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