25 Mar
2021
25 Mar
'21
12:47 a.m.
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:
via
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
> > 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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