Hoard-of-bitfonts: bitmap fonts from disused operating systems

Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by phkahler on Thursday July 08, 2021 @01:20PM (#27775086)

I still have my original Interact computer which is not listed. The text on that is 5x5 pixel characters with 1 pixel in between, so 6x6 but the gap is not encoded in the font. Only upper case characters were supported. The font is not in a separate prom, it's in the main 2K eprom along with the tape read/write functions and some very simple keyboard scanning and pixel, box, and text rendering functions. I think a ROM dump exists somewhere online, so with the above description someone should be able to locate the character set easily enough. Probably the worst one you'll ever see.

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Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by Someone on Thursday July 08, 2021 @01:47PM (#27775470)

Looking at the screen shots in https://www.old-computers.com/museum/software_detail.asp?st=..., it doesn’t look bad.

Of course, those are lying. https://www.old-computers.com/museum/computer.asp?st=1&c=100... says “The Interact shipped with 2 joysticks, a built-in tape recorder, a TV RF modulator and 2 KB of ROM”.

So, in real life, those characters were filtered through a NTSC tv signal.

Also, the last comment on https://www.old-computers.com/museum/doc.asp?c=1004 claims “It had no character generator, formin it's large letters from graphic routines.” That seems to imply all characters were drawn procedurally, not from a bitmap font. I find that unlikely. Can that be done in less memory than a generic blitter would use?

There even is a link to emulators on https://www.old-computers.com/museum/emulator.asp?c=1004&st=.... One of them led me to http://dchector.free.fr/link.html, which has a few emulators for (AFAIK) obscure systems such as “Thomson MO5NR, Thomson MO6 & Olivetti Prodest PC128” and http://dchector.free.fr/download/interact_rom.zip, which, presumably, is the ROM for this system.

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Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by megameter on Thursday July 08, 2021 @03:32PM (#27776636)

The term "character generator" in video specifically refers to hardware that overlays text onto the video signal. That is, in this case it's not a "text mode", it's a bitmap graphics mode used for text, which appears likely just going by the screenshots. There weren't many computer systems taking this approach in 1978, since any bitmap mode would be RAM-hungry, so they were usually either text centric(Commodore PET) or had both text and graphics modes and hybrids(Apple II, Atari).

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Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by LocalH on Thursday July 08, 2021 @02:09PM (#27775743)

It probably means the hardware had no dedicated text mode with a separate character ROM, but that the software would draw the bitmaps to the graphics screen itself.

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Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by phkahler on Thursday July 08, 2021 @08:23PM (#27779227)

We disassembled the 2k rom back then. There are routines for drawing text, character by character, pixel by pixel. The code is terribly not-optimized but fits in 2k including the character set. Hardware just has a single frame buffer at a fixed address. 4 pixels per byte, 32 bytes per line, and that includes over scan and horizontal blanking so 112 to 114 pixels wide 3 scan lines tall. Doubling the pixel clock, devoting more ram to it, and using the empty rom socket would have made it quite a machine for back then.

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Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by tenebrisalietum on Thursday July 08, 2021 @01:36PM (#27775305)

I think the DEC VT05 font is similar, but I can't even find any good closeup pictures of the screen (just ones that show the whole unit, but don't really show the detail of the screen).

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Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by GekkePrutser on Thursday July 08, 2021 @05:38PM (#27777919)

Did you ever use a real VT05?

I love serial terminals and I love the design of the VT05 (even though I know it's wayy too deep for a modern desk). It's just so cool and futuristic in a 70s star trek kind of way.

I also heard it wasn't simply a small microcomputer, it had everything in discrete logic on many PCBs which seems to be why it was so big. Really cool. I'd love to see one some day.

I volunteered at a computer museum that had a lot of DEC stuff but we had nothing older in terms of DEC terminal sthan VT100s. I still own an amber VT520 (though from the Boundless era after the terminal business was sold by DEC)

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Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by tenebrisalietum on Friday July 09, 2021 @11:33AM (#27784728)

Nope, never used a real one. Yeah, from what I was reading it didn't have a single-chip CPU - but that's to be expected as the VT05 was introduced in 1970 and Intel didn't release first single-chip CPU 4004 until 1971.

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Re:Hoard-of-bitfonts: bitmap fonts from disused operating sy... by LocalH on Thursday July 08, 2021 @02:08PM (#27775730)

Reminds me of the Fairchild Channel F font a bit

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