Dieter wrote:
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?
The Ethervideo box isn't a "video board", it is more like an X11 terminal.
It could be an X terminal, or not. What is apparent is that there are
clearly two cases here.
1. The box can function as the video card for a PC. In this case,
Ethernet is functioning as just a fast serial interface and would be
connected directly to the PC's Ethernet connection with a RJ45 cable --
like my DSL box is connected. Or, could it simply respond to any
address if the senders IP address was 127.000.000.xxx? But, that might
be a security issue on a network.
2. The box could function as a video display on a network. It would be
reached by a router or coax. In that case, it would not act as the
primary display for a PC.
If we want to use it as the console of a pee-cee, there would need to be
some sort of "PC Weasel" type card with VGA-to-X11 bios firmware. That
could be an optional feature. Systems that support some type of open bios
could put the code in there and not require a slot.
Yes, IIRC, I have one of those boards somewhere (I have a bunch of old
PC hardware) that is used to upgrade the hard disk BIOS routines. As I
said, some systems or network cards have a socket for additional BIOS.
Or, Open BIOS would be good also.
So, how would the VGA-to-X11 bios firmware know what IP address to use for
itself?
How would it know the IP address of the Ethervideo box that is its console?
Well, my DSL box has a fixed IP address. Doesn't a slave device have to
use a fixed, or hardware selected, IP address?
I suppose that the box should have an IP address so that a small local
network was possible even in case #1. However, I really think that a
network port dedicated to only the console display is the best idea for
case #1.
This raises the question of how will the IP address of the box be
determined. If it is going to be possible to have multiple boxes on a
network that they can't all have the same fixed IP address. Would the
box have (for example) two of those rotary replacements for DIP switches
so that you could set the last two (Hex) digits of the fixed IP address.
That sounds like a reasonable idea. In that case, only '00' would
function as a console display. So, the box would have a fixed IP
address if functioning as a console display and the BIOS add-on would
know that address.
Will it ask the Ethervideo box to create a new window (like xterm -C)?
No, it would be functioning as the whole display in VGA BIOS mode for
boot and would be controlled by a driver after that. What it would do
after boot would be totally controlled by the driver and the software
using the driver just as it is with any other video card.
There could be multiple Ethervideo boxen on the network. There could be
multiple headless computers on the network. A single Ethervideo box
could provide the console for multiple computers.
This is something that would need to be considered. As it is with an
internal video card, you need to connect a display to a headless system
to configure it and then after that you just don't see the boot messages.
IIUC, what you are talking about is having a virtual (non-hardware)
replacement for a KVM switch. This could work with a box that had a
CPU. This is an issue that would need further consideration.
We need a way to configure this stuff and avoid chicken-and-egg problems.
Fixed (hardware settable) IP addresses should avoid bootstrap (chicken
vs. egg) issues. If the box (with a CPU) needs to know the IP address
of the network administrator then you would have to have persistent
memory for that. If the box needs to be configured, then the network
administrator would have to configure it before other PCs on the network
were started. With a box that has a CPU (probably running X11) it might
be a good idea to have a flash card to store various data such as IP
addresses.
And we need to avoid security problems, as consoles are normally considered
secure.
Yes, security issues would need to be considered. We might already be
supporting encryption for HD digital video content which could be used
for other transmissions as well.
I was thinking in terms of connecting my TV to my home network. My
major security issue is to keep my cat from trying to type when I am not
at the console. He has managed to screw it up to the point that I had
to reboot once.
I think that I am suggesting that two models would be a good idea for
the two different cases although one that could do case #2 should also
be able to do case#1. The more advanced (#2 model) would have a CPU, a
flash card socket (this means that it could be configured by storing
data in the card on PC) and could run X. The simpler model would not
have a CPU and might have a hardware settable IP address. Although if
we used a chip that directly supported a flash card and had a MCU, a
flash card might be the best way for the non-CPU box to be configured.
Clearly, there are various possibilities to address these issues.
--
James Tyrer
Linux (mostly) From Scratch
_______________________________________________
Open-hardware-ethervideo mailing list
[email protected]
http://lists.duskglow.com/mailman/listinfo/open-hardware-ethervideo
