Make your own bitfonts

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Wow, I once wrote a custom character set generator on my Commodore 64. It used a combination of Basic and assembly and I was nearly finished with it when my hard drive crashed and I lost everything.

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OK, this is weird. In 1987 I wrote a program on my Apple II Panasia clone (48K with no lowercase) in Basic that let you draw your own characters and use some fancy pokes or something I have no memory of now to get them usable as a font. This was one of the longest and most complicated program I had written to date, and when I was nearly finished the floppy disk stopped working and I lost everything.


Poking was always a fraught with difficulties, not that it had anything to do with your drive dieing. Oddly, you might have been able to save the program using the speaker/headphone out to a tape deck. I know that was possible and I think it was part of the kernel.

I read an article in an computer magazine about using pokes to alter the existing DOS that was loaded into memory so one could use any word as a command or get any text as feedback. Ostensibly it was for, as I remember, customizing DOS so that one could load a program with just ‘L’ or to customize the prompt, or localize DOS for a language that it hadn’t be localized for. (It hadn’t been translated to many at the time.)

Well I was a kid, and fart jokes were pretty funny so I made a program that allowed one to use crude language to get tasks done. It was a big hit, copied- it still may be floating around there. It was called DDOS, ‘D’ for ‘Dirty’ and it was a juvenile as you could imagine.

It was so well liked that a teacher saw it, and rather than chew me out, or all my parent, or give me detention he pulled me aside and asked how I did it. That was it, along with I couldn’t use it at school. I could though use the code that changed the prompt and cursor. Word got around the lab and we didn’t load that program ever again. I still see that teacher from time to time, and he remembers other shenanigans and even saved one of my projects. I remember him liking the phrasing for errors. “Well you got that right!”

I hadn’t thought of using pokes or Apple BASIC until you posted that. I still have a bunch of call numbers memorized in my head.

Note: I think there were problems with changing the first letter of some commands, or outputs. I can’t remember.


When I first discovered the existence of the secret “machine language” that lived inside my C64, and I began trying to understand what it did, I realized OMG it’s ALL about POKING stuff. In fact, that’s all computers are really doing half the time. Just storing byte(s) somewhere at a location in memory. At the time though I remember it was a very important revelation to the 13 year old me.

Dude, parallel universes or something!


Speaking of poking, I relied heavily on this book, which basically explained what every reserved byte or memory mapped IO register was for on the Commodore 64. It was indispensable .

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