Friday, November 26, 2021

Spent hours organizing DMS files and testing all the COMMON programs I have archived

 DMS FILE ORGANIZATION

I took the batches of cards that I had read, clumped them into larger groups and then split them into the individual phases that are loaded during and initial or reload of DMS onto a disk cartridge. You end up with many, many dozens of phase files plus other files that are assembled into a huge virtual card deck. On the real machine, that deck is loaded in the card reader, a blank disk cartridge is inserted in a drive, and then the deck is loaded by pushing the boot button (Program Load) on the 1130.

A deck consists of the following:

Three loader files in sequence. First, a single 1130 loader card that is the subject of the boot operation. That card's program then reads in a single card that is the 1800 loader; the 1800 is the big brother of the 1130 which was used for real time process control tasks. Finally, the 1800 loader program reads in a multi card deck which is responsible for reading in the system loader. 

The system loader is split into two phases. The first begins to format the disk cartridge and reads the next set of cards which are the data and permanently resident system code areas that are put in the special boot areas of the disk cartridge. After this 'EMN' permanent code and data file comes the system loader phase 2, which is the logic that reads most of the deck of cards and stores each phase on the disk.

A few control cards are inserted by the user that define the peripheral configuration, storage size and defines the ranges of phase numbers for each of the major sections of the monitor system. These are functional areas such as the job control, disk update program, fortran compiler, assembler and core image loader. 

The last phase of the monitor is followed by a 'type 81' card which tells the loader that it through with loading phases onto the disk libraries. The machine then fires up the monitor and runs the DUP program to start loading the system library components such as functions and subroutines. These are small object decks with a *STORE directive in front of each one. After the long string of library components is loaded, the process ends and the disk is now ready to be cold started by hitting Program Load with a cold start card in the reader. 

I have archived one complete deck to load the older V2 M11 version of DMS, a second complete deck to load the newest V2 M12 version, and have started on a third deck which is also a DMS V2 M12 load. Since I have multiples of the deck and have versions of the card decks from other sources, I can do a compare to make sure that I didn't garble any code during the archiving. 

I ran a few comparisons already with no differences detected. As a test I compared the System Loader Phase 1 decks between the two version, M11 and M12, which did flag a reasonable number of differences. I will continue to work with the files until I have compared and verified everything. Preservation of the 1130 system files is the most important aspect of this archiving for me.

TESTING THE PROGRAMS FROM COMMON AND IBM PROGRAM DISTRIBUTION

I have reviewed all the files I have archived, written a short description of what they accomplish, and tested them on the IBM 1130 Simulator as much as feasible. In many cases I include part of the virtual listing from the line printer, particularly for printer art. 

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