Inconsistency in sim_card.[ch]

[bsdphk]

I'm trying to decide on a preservation format for punched cards in datamuseum.dk, and sim_card seems to be the only place anybody has given it any thought.

Of the four supported formats, only two a general (ie: can store any hole combination) and surveying bitsavers, the "Binary Card format" wins 360+ to 8 over the SCN format.

However, sim_card.c and sim_card.h do not agree about the format.

sim_card.c says:

    Binary Card format:
            Each record 160 characters.
            First characters 6789----
            Second character 21012345
                             111
            Top 4 bits of second character are 0.
            It is unlikely that any other format could
            look like this.

sim_card.h says:

    Binary Card format:
            Each record 160 characters.
            First character   21012345
                              111
            Second characters 6789----
            Top 4 bits of second character are 0.
            It is unlikely that ascii text or BCD format
            text could produce similar profile.

Note that they disagree about the order of the two characters and that the "Top 4 bits..." line makes no sense in either of them.

I have surveyed our local mirror of bitsavers and there are 360+ files which conform to the sim_card.c description and no files which conform to the sim_card.h description.

I have no idea if the files on Bitsavers work with Open-SIMH, but I assume the do ?

If they do, can I suggest one of you change the description in both of the files to something like:

    Binary Card format:
            Each record 160 bytes, two for each column:
                    |--------+--------|
                    |        |111     |
                    |6789zzzz|21012345|
                    |--------+--------|
            z = This bit is always zero.
            The ".crd" filename extension is strongly
            recommended for this format.

Thanks in advance,

Poul-Henning

(Digital preservation volunteer in Datamuseum.dk)

[pkoning2]

On Oct 1, 2025, at 5:50 PM, Poul-Henning Kamp ***@***.***> wrote: bsdphk created an issue (open-simh/simh#503) I'm trying to decide on a preservation format for punched cards in datamuseum.dk, and sim_card seems to be the only place anybody has given it any thought.

I would have to dig for the precise references, but I remember some work related to preserving punched cards that included not just the bits on the cards but also additional information, such as what kind of cards were used. It's a bit like preserving magnetic tapes simply as .tap files vs. capturing in addition the information written on the tape reel. It may be that Paul McJones was the author of the card preservation proposal, but I don't remember for certain. paul

[rcornwell]

Thanks for the reminder. I push a PR to update header file.

[bsdphk]

The pull request is #504