Sunday, December 6, 2015

Working with DMS card decks and my utility program

I am in Las Vegas for the week, working heavily, but I did manage to do some work on the flight over and in spare time tonight.


I worked on the raw files read from all the decks, converting them to individual decks per phase so that they can be combined as needed in system loads. I also created a separate copy of the decks for the COBOL and RPG compilers.

I updated my program to punch out decks from any existing disk cartridge, merging in the phase header text for RPG and a few missing phases. Only COBOL lacks the header cards and all others are now going to match the versions shipped by IBM.

Another improvement I made was to punch the separator cards (a card with the character 9 punched across all the columns) only where they were punched from the IBM distribution cartridges. These occur after phases 12, 39, 74, 84, 98, A1, CE and F6 plus I added one after the COBOL and RPG compiler phases at 5C and CC respectively. These cards allow someone to find the breakpoint in decks which are punched, since they have no printing atop the card. The pattern of 9s is very distinctive and easy to spot.

I have to read in all the library modules, which are handled differently from the system phases. Library modules are saved in the regular file area and manipulated by the Disk Utility Program (DUP) just as with ordinary user programs. System phases, on the other hand, are only loaded by the System Load process and exist in a system area on the disk that is not intended to be visible to the user.

Each library program comes with a DUP control card (e.g. a *STORE     CD  UA    FILENAME) in front of the object deck. The system load process, after handling the system phases, sees an "81" card and starts up DUP. DUP will read all the subsequent cards, which are these combinations of a DUP command and the object decks. The user can always change one of these without having to do a system load of any type, just by running DUP.

I have a few small decks to scan as well - the front end program to start the system load, the cold start card, and the sample programs that are shipped on the IBM distribution cartridges. It is my intent to have all the cards to allow me to produce a complete distribution cartridge.

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