Dieter wrote:
James> If it is the a PC system's only video board, it must do VGA.
Huh? How do you propose to get a pee-cee's crappy bios firmware to
talk to a console over Ethernet?
The video BIOS is separate from the PC's BIOS. It is on the video board
and the boot routine installs it based on a header that is read by the
main BIOS during boot up. So, the video BIOS interrupts call the video
BIOS code on the video card.
So, since the PC BIOS probably won't know how to find a peripheral over
Ethernet, it would be necessary to add a BIOS chip to the PC which the
PC would install when it booted. So, now the BIOS knows how to
communicate with the card over Ethernet. If all access to VGA is based
on the defined VGA BIOS interrupts, then all should work fine. A good
PC BIOS should only communicate with VGA using VGA interrupts. That is
how the IBM AT BIOS works (I have the source code -- IBM used to publish
it).
James> Yes, but a video board is a slave system, it must do what the main
James> system requires.
Does it need to be able to function as the only video board on the system?
This isn't a video board that plugs into PCI/PCIe. It is a separate node
on the Ethernet.
Yes, the PC communicates with it by Ethernet rather than PCI/PCIe. But
a bus is a bus, it doesn't affect the functions of the board as long as
communication can be established.
Daniel> I do not know anybody who would like to configure his BIOS settings or
Daniel> install operating system on an Ethernet attached display.
That would be nice to have, but as above, it is not obvious to me
how to accomplish this, unless you propose a "PC Weasel" type card
with Ethernet instead of RS-232? (That would then talk to the Ethervideo
box over Ethernet.) Am I missing something?
I would use the Ethernet that is built into most new PC motherboards.
All that is needed is the firmware (BIOS) to use it to communicate with
the card.
Daniel> It is very
Daniel> inefficient to focus on that, as everybody has a display today
Actually a lot of computers are headless.
I got my NEC MultiSync XV15+ free at the dump. :-) But seriously, as I
said, most OSS/OS systems are white box. Either user built or put
together by a "screw driver" shop.
Daniel> Maybe it would be better to re-clarify the requirements here again, if
Daniel> it should lead to some product..
The requirements should be in the list archives. Is there something that isn't
clear?
James> That is out purpose here, to make a video card for users of open
software.
No, the Open Graphics list is trying to build a video card.
The Ethernet Video list is trying to build a separate box that connects to
the Ethernet. Basically an X11 terminal that can also decode video (e.g. mpeg).
Here being this specific list: OHE.
James> The requirements were fairly clear: a video card that is external to the
James> system connected by a serial connection (Ethernet, USB-2, or IEEE-1394).
USB is a crappy standard, and USB-2 is limited to IIRC 5m (about 15 feet).
IEEE-1394 is much better than USB, but is also limited to 5m. 1394 can use
repeaters, but that runs the cost up, and requires power. There was talk about
a newer version of 1394 that would use cat6-ish wiring, same as recent Ethernet,
and allow longer distances, did that ever get anywhere? Ethernet can go long
distances, is inexpensive, and very common, so Ethernet is the clear winner.
I agree, USB sucks. Ethernet is probably the preferred connection
method if IEEE-1394 won't use a long enough wire without going to fiber
optic. I didn't mention WiFi but I notice that TVs are starting to use
it. IAC, we would be using Ethernet over wireless.
--
James Tyrer
Linux (mostly) From Scratch
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