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Thread: Original Hercules MGA Card - cant it work?

  1. #21
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    Quote Originally Posted by Chuck(G) View Post
    Does anyone know of a ISA monochrome (MDA/MGA) card without a printer port?
    Well, I know a few CGA/Hercules cards that don't, like the ATi Small Wonder and Paradise PVC4. But monochrome-only cards? Don't think I've ever seen one without printer.

  2. #22
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    Exactly. I've owned several (even a "Herc Plus") and don't recall ever seeing one. So dithering about the printer part doesn't seem to make any sense.

  3. #23

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    Quote Originally Posted by Chuck(G) View Post
    Does anyone know of a ISA monochrome (MDA/MGA) card without a printer port?
    I saw such a thing.
    AFAIR it was some typical HGC clone, only cost-reduced, with empty room for the 25-pin connector and LPT chip.

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    Could it be just a product of the period? Monocrhome was the standard for PC graphics and most computers may only have come with a Serial Async card; so for some odd reason graphics and Printer ports became a combined thing.. I have a lot of old early 8 bit isa cards that are all Hodge podge messes of different connections. I dont know really, just a guess.

  5. #25

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    They were just following IBM's example. A monochrome text display and a printer port were the minimum necessary to get office work done, so IBM was wise to combine them onto one card.

    The aftermarket monochrome cards without a parallel port were probably intended for clone systems which already had a parallel port built into the motherboard.

  6. #26
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    I believe that IBM also reserved a port address (3BC) for the printer port on monochrome display card. Printer port cards by IBM used other addresses.

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    Quote Originally Posted by Chuck(G) View Post
    I believe that IBM also reserved a port address (3BC) for the printer port on monochrome display card. Printer port cards by IBM used other addresses.
    Yes, IBM reserved addresses for 3 printer ports:
    3BCh, 378h and 278h

    So in the early days, LPT1 was usually 3BCh, because it was on an MDA card.
    A separate printer port card would use 378h or 278h for LPT2 or LPT3.
    The IBM Printer Adapter is at 378h: http://minuszerodegrees.net/oa/OA%20...%20Adapter.pdf
    (Note that this is such an early manual that it seems they just copy-pasted parts from the MDA manual, and forgot to change the 3Bxh addresses in some places to 37xh).

    I am not sure what the reason is exactly, but most clones had their printer port at 378h, so this became the de-facto LPT1 address once MDA and its onboard printer port went out of style.
    Perhaps they used port 378h to allow for an MDA or Hercules card to be installed without having to give up the printer port on the clone.
    Or perhaps by the time these clones came around, most people had already ditched their MDA/Hercules cards, so printer ports at 378h were far more common than those at 3BCh.

    Either way, by the late 80s, 378h was the standard for LPT1.

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    Quote Originally Posted by Chuck(G) View Post
    That 640x480 was not for everyone--if you didn't have a program that made use of the PGCs graphics primitives (i.e. drawing commands), you got plain old CGA emulation. Somewhat akin to the later TIGA boards.

    More notable and earlier, was the NEC APC (640x475) in 1982. Even the Olivetti M24/AT&T 6300/Xerox 6060 could do 640x400 in 1983.

    CGA-type graphics were really way behind state of the art.
    Epson had a very nice display, if you didn't mind monochrome graphics. The QX-10 could do 640x480, and the text was fantastic. The QX-16 could do monchrome CGA, but my QX-16 hasn't worked in a while; I don't remember if it could switch from 640x200 mono CGA under MS-DOS to 640x480 monochrome graphics under CP/M.

  9. #29
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    I was still using Herc Plus cards well into the 2P+2S adapter cards (they lasted into the 386 era). IIRC, the display card printer port was always LPT1. You could change the assignments, however, by juggling low (BIOS) RAM tables, if you had an application that didn't ignore the BIOS LPT table.

    Herc Plus had the very cool RAMFont feature, if you had software that used it.

  10. #30

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    Quote Originally Posted by Chuck(G) View Post
    I
    Herc Plus had the very cool RAMFont feature, if you had software that used it.
    I have a Herc Plus and the MS Word 5.5 does make use of it. You can have like 80x43 columns on that and looks great

    I also have the original hercules one.

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