Mystery graphics card from eBay: what is it?

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Күн бұрын

Пікірлер: 20

@AnonyDave 2 ай бұрын

Only thing I can think of that I don't think was mentioned would be to dump the bios chip on the board. Just maybe you'll get lucky and it'll have some strings from the manufacturer

@sparthir 2 ай бұрын

Dumping the ROM regardless would be good for archival purposes anyway. 😊

@AnonyDave 2 ай бұрын

@@sparthir oh yeah, that too

@andyhu9542 2 ай бұрын

The issue is that the ROM is not a BIOS, but character font. So it will just be binary bitmap representations of letters and digits. It won't contain any more information than what's written on the board.

@AnonyDave 2 ай бұрын

@@andyhu9542 oh right, I'd totally forgotten that back in that era they didn't need an extension rom for the basic video functions 😅 I've definitely forgotten more over the years than I'd like to admit

@PaulLoveless-Cincinnati 2 ай бұрын

@@andyhu9542very interesting! I did not know that either. I am 35 and got deep into computers around age 12.

@tw11tube 2 ай бұрын

This card is *very* likely a Hercules compatible card. The SRAM on that card is not for redefinable fonts. The (original) Hercules card does not have redefinable font. The later Hercules Plus (aka Hercules RAMFont) does, but this card is clearly not a Hercules RAMFont card - the architecture is different. You are correct about the second DIP40 chip on the Hercules card, the "VIDEO 100" chip is a Hercules custom chip that integrates some logic functionality to reduce the chip count on the Hercules card. Now, what is the SRAM really for? The SRAM on the Hercules card is an "attribute cache" or a "character cache". While the ISA interface is 8 bits, text mode actually is a 16 bit architecture: It requires an attribute byte and a character byte for each displayed character. So for refreshing the display, a 16-bit memory bus would make sense. The CGA does not have a 16-bit memory bus, so it needs two memory cycles per character. This loads the memory system on the CGA so hard that it can not support processor memory access during the active video time without image artifacts ("CGA snow") in 80-character text modes. To relieve the memory system of the Hercules cards, either the character codes or the attribute bytes are copied into the SRAM as well as the DRAM when that byte is written by the CPU, so the card can fetch one part from the 8-bit SRAM and the other part from the 8-bit DRAM. As the SRAM is just 16 kbits (2 KBytes), it can only contain character (or attribute) codes for 2048 characters. At 80*25 is already 2000, this implies there is no support for multiple text pages that can be switched on-the-fly, while the CGA with just 16K of video RAM can provide 4 pages of 80*25 or 8 pages of 40*25 characters.

@andyhu9542 2 ай бұрын

Thanks a lot for the information!

@joshhiner729 2 ай бұрын

Regarding the graphics market in 1988: Looking at my 1980’s pc magazine volumes you can see XT clone machines with monochrome Hercules or MDA advertised up to 1989 (and probably later but I cant find my 90s volumes). I used an XT until 1992 (but with cga). All of the pcmagazine ads for xt clones (and there are a ton) start with base xt’s with no hard disk, one or two floppies, monochrome and 640k. Even xt ram upgrade boards are sold into the 90s. The 80s to early 90s were an interesting time with old model lines (apple ii, commodore 64, even atari 2600) lasting for 10 years or more into the early 90s. A somewhat different time than today where three years pass and the device is ancient heheh.

@andyhu9542 2 ай бұрын

I didn't live back then so my views are definitely biased. This is the conclusion I ended up with, though. Flipping through old computer magazines and I realize that the life of hardware was just longer back then.

@Illusiono 2 ай бұрын

Compro 88 was a British IBM clone from "computopro" ? .. They had a monochrome graphic/parallel port card which probably was a Hercules knockoff. I think IBM filed a lawsuit against the Compro 88 so probably short lived

@derwolf7810 2 ай бұрын

I would guess the same: The 'Compro 88 PC Clone' (probably containing that graphics card shown in the video) was built by 'Computoprocessing Ltd' (got dissolved in 1993).

@derwolf7810 2 ай бұрын

I found some links (which i URI encoded to hopefulls avoid this post automatically being deleted, you have to decode those links, though): - Commercial on pages 15 and 16 of the journal "Practical Computing" (January 1986, Volume 9) https%3A%2F%2Fmanuals.plus%2Fm%2F15610dfe323e26efff8685fc6898d71bec6685ad98ff57518ece3343e78d0b80 - newspaper article on page 13 in the Computerworld (July 21, 1986) https%3A%2F%2Fbooks.google.de%2Fbooks%3Fid%3DMliquQJ74H0C%26pg%3DPA13%26lpg%3DPA13%26dq%3D%2522COMPRO%2B88%2522%2Bpc%26source%3Dbl%26ots%3DvZO1-po3_s%26sig%3DACfU3U0bbSpVo1cOOmQOpcY_JfuLEClmPw%26hl%3Dde%26sa%3DX%26ved%3D2ahUKEwiwhqLkn_WGAxWJSfEDHRZ5CbIQ6AF6BAgaEAM%23v%3Donepage%26q%3D%2522COMPRO%252088%2522%2520pc%26f%3Dfalse - another newspaper article on page 16 in the InfoWorld (July 28, 1986) https%3A%2F%2Fbooks.google.de%2Fbooks%3Fid%3DVy8EAAAAMBAJ%26pg%3DPA18%26lpg%3DPA18%26dq%3D%2522%2BCompro%2B88%2522%26source%3Dbl%26ots%3Dba3OqwG9c7%26sig%3DxmuOtbEaxVmbE04KdRh1fYKWdxI%26hl%3Den%26sa%3DX%26ei%3DaNvcUOuvIs-50QHejoDACQ%26redir_esc%3Dy%23v%3Donepage%26q%3D%2522%2520Compro%252088%2522%26f%3Dtrue

@andyhu9542 2 ай бұрын

Mystery solved!

@watchmakerful 2 ай бұрын

Yellow rectangular capacitors are definitely modern (2000s or later).

@ernestoditerribile 2 ай бұрын

Just put in in an Old 8088 machine or a 286 with an ISA socket, it is a Graphics/Parallel card. With an old Hercules monitor you should get an output.