MaxSpeed VGA MaxStation

Warner Losh imp at bsdimp.com
Thu Mar 25 02:47:53 CDT 2021


ISTR there were a few DOS-only video cards that had VGA outputs, but only
did text mode for point of sale applications. I never used any of these
myself, though...

Warner

On Thu, Mar 25, 2021 at 1:46 AM John Ames <commodorejohn at gmail.com> wrote:

> Hah, wow.
>
> On 3/25/21, Warner Losh <imp at bsdimp.com> wrote:
> > On Thu, Mar 25, 2021 at 1:01 AM John Ames via cctech
> > <cctech at classiccmp.org>
> > wrote:
> >
> >> Huh - wacky. Still pretty curious how it works just on a basic "how
> >> the hey does the framebuffer even function" level, but that's
> >> certainly interesting. Does make me feel less guilty about planning to
> >> cannibalize it for a homebrew project later, though!
> >>
> >
> > It's a text mode, which generates the screen image using rasterized fonts
> > from the text + attributes stored in video memory.
> >
> > There is no frame buffer. With that little RAM it can support the text
> > modes easily enough, but none of the graphics modes.
> >
> > Warner
> >
> >
> >> On 3/24/21, Camiel Vanderhoeven <camiel.vanderhoeven at vmssoftware.com>
> >> wrote:
> >> > It's neither X nor ethernet. These worked with a special controller
> >> > card
> >> > that had 4 RJ45 connectors. That allowed four users to share a single
> >> > Windows NT system.
> >> > ________________________________
> >> > From: cctech <cctech-bounces at classiccmp.org> on behalf of John Ames
> via
> >> > cctech <cctech at classiccmp.org>
> >> > Sent: Thursday, March 25, 2021 4:41 AM
> >> > To: cctalk <cctalk at classiccmp.org>; cctech <cctech at classiccmp.org>
> >> > Subject: MaxSpeed VGA MaxStation
> >> >
> >> > So, some months ago, I was in an electronics surplus store and picked
> >> > up what was obviously an X terminal - tiny metal slab with a VGA
> >> > connector, serial & parallel, AT keyboard, and RJ45 "communication"
> >> > port. I got it bare, without the external PSU that would've gone with
> >> > it, and I've since been unable to determine just what the heck I'm
> >> > supposed to feed this thing. It's a standard barrel jack, but there's
> >> > no markings on the case or the PCB to give any clue as to what
> >> > voltage/amperage or polarity it expects, and Google has been no help
> >> > at all. Does anyone have any recollection of these things? Any idea
> >> > what they want for juice?
> >> >
> >> > To throw an extra mysterious wrinkle into this, when I popped open the
> >> > case to get a look at the PCB, I found that, apart from the CPU, DART,
> >> > and ROM, the only non-glue ICs on the board were an 8K SRAM and a
> >> > W82C476 RAMDAC - but 8K isn't even remotely enough for a VGA screen,
> >> > not even a monochrome one at VGA resolution! Am I missing something on
> >> > how these things operated? Given this, my only guess would be some
> >> > kind of insane networked-framebuffer scheme where the host would blast
> >> > video data in on the fly, but there's no way this was even 100Mbps
> >> > Ethernet, and 10Mbps isn't nearly fast enough to transfer 150KB at
> >> > 60FPS, and there's no memory to buffer it for a slower refresh. What
> >> > in the heck is going on here?
> >> >
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>


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