foliagecanine wrote:
There are several people who have made Arduino-based punch card readers. Theoretically this could be considered a custom format.
However, it's rather hard to "write" to the punch card with an Arduino, and practically impossible to "re-write."
Yeah, I've found plenty of homemade paper tape / card reader projects online, but I'm not sure I've found one project for a ground-up punch (there are a few for restoring old punches). But the difficulties in making a punch would primarily be mechanical, I wouldn't expect the Arduino programming (or whatever controller you're using) to be that much more difficult.
I've wondered about whether in the modern day it might be easier to use something like a receipt printer (though printing on something a bit thicker than receipt stock to reduce the likelyhood of tearing/crumpling in handling or tearing/crumpling/jamming in the reader). You'd just print black squares instead of punching (if you were doing cards rather than tape, you might opt to use an existing QR code format of appropriate dimensions and capacity). It seems like it should be doable to frankenstein an Arduino to some sort of existing printing hardware to create a card or tape "punch". "Rewriting" would basically have to be done by appending a diff to the end of a tape/card data set.
Quote:
Magnetic media ... would be much harder to make at home.
A hard disk certainly would be. I'm less certain about floppy or tape media. Especially tape. Putting together a homemade drive, getting some kind of dust jacket onto the disk, and making sure everything was rotationally balanced would be a pain for a floppy, but tape should be much simpler to deal with mechanically, and I'm pretty sure that the ingredients for the actual medium itself for a floppy or magnetic tape are just plastic film, glue, and finely powdered rust. One might not achieve the storage densities for homemade tape that one would for professionally manufactured tape, but it seems like one of the more home-manufacturable media. Mechanically and electronically it would probably be *easier* than any kind of punch/printer for paper storage, the big issue would be manufacturing the tape itself. Audio cassettes are even making a comeback due to music nostalgia, and cartridge magtape is still very much in use for datacenter backup storage, so:
1) A lot of the old 8-bit home computers used an audiocassette in an off-the-shelf tape player for storage (the user had to start and stop the tape himself). All this requires is an audio jack and a driver to modulate/demodulate the audio signal.
2) One could frankenstein an Arduino to a tape player to get a drive with automatic start/stop/rewind.
3) One could purchase audiocassettes and strip the tape out for use in a format convenient to the user.
4) One could potentially buy audiotape straight (without a cassette), though my understanding is that most cassette manufacturers these days are manufacturing tape in-house, not outsourcing, so finding audiotape outside of a cassette may be difficult.
5) Depending on use case, one might just buy a tape drive and a stock of tape cartridges. Or, one might figure out how to frankenstein a tape drive (if you're trying to use it with an old machine that doesn't have modern storage ports, or something that you cobbled together on a breadboard, or whatever).