Dieter wrote:
<SNIP>
We need for the VGA-to-Ethernet-X11 card to provide the computer's
firmware with whatever it actually needs for a console. I think that
is a "VGA text interface", but maybe there is some braindead bios out
there that requires a framebuffer to draw graphics in?
I would hope that a BIOS would access the frame buffer using only the
VGA BIOS routines. It is possible to draw graphics with VGA BIOS calls,
but I don't think that most BIOSes use those. There are also CGA BIOS
calls for graphics that draw little blocks which are larger than pixels.
It is an independent node on the Ethernet.
X Window or MS Windows would still have to have a video driver to
communicate with it.
X clients do not require a video driver to communicate with an X
server. The X server requires a video driver to drive the display.
In our case the X server would be in the Ethervideo box, and the X
client would be in the VGA-to-Ethernet-X11 card.
Yes, if we had an X server on board it would simply be a remote login.
It would only be for an OS that wouldn't do X that a driver would be
needed. Or, if you had a card without an X server you would always need
a driver.
At least some of the SOCs include small CPUs. I'm not sure if a
pure DSP could run X or not?
IIUC, DSP chips can run an OS -- they have registers and an ALU.
However, it appears that the consensus is that it is more efficient
to have at least a small MCU to do that.
What does MCU stand for in this context?
MicroController (as opposed to MicroProcessor [MPU]). My context was
not exactly clear. I have probably insulted the ARM by calling it a MCU.
If there is no CPU,
I was making a distinction between a CPU such as an x86 and a more
simple MCU such as an ARM
I was under the impression that ARM was a general purpose CPU like
x86, Alpha, Sparc, etc. as opposed to a DSP with a very specialized
instruction set.
ARMs have become more powerful over the years so although the 7 isn't
nearly as powerful as a Pentium, it could probably run X.
how do you get data from the Ethernet port to the decoding
hardware?
I suppose that that would depend on the Ethernet chip but it would
probably be onboard the decoding chip. If using a DiVinci chip
[for example], the Ethernet interface and an ARM MCU are onboard.
The ARM could take care of the Ethernet traffic whether or not a
more powerful CPU was needed to run X.
How powerful is the ARM in the DiVinci? Web page says 32 bit, MMU,
up to 300 MHz. I haven't studied the ARM arch or how it compares
with others, e.g. 300 MHz ARM ~= xxx MHz x86? Unless this thing is a
lot more pathetic than it sounds like, it should be able to run an X
server.
I think that it could run a basic X server, at least TI seems to think
so. The only question would be about running OpenGL.
Is there a variety of flash card or similar device that the box
could write IP addresses to, then the memory gets moved to the
bios card?
If the computer has a flash card socket and the Video BIOS socket
was flashable. This would work fine for distributing video on a
network, but if it were the only display for the computer, you have
the bootstrap problem again. This used to be solved by using a
bootable floppy with DOS and a program to flash the BIOS. Do new
systems have floppies? Well I guess that if they don't have
floppies that they have a bootable CDROM or DVDROM drive.
And be inexpensive enough?
The prices keep falling every day. They are (parallel) ATA, so
most chips that I have looked already have the interface. All that
is needed is the socket. They just look like a small HardDisk.
No, not a SSD, some form of memory that can hold the bios firmware.
XIP [eXecute In Place]] flash memory is a different thing. The cards
are so handy that it would probably be best since there is almost
nothing needed for an interface -- most chips like the DiVinci have the
interface for cards so that they can display pictures/video -- it would
be best for the system to boot and then read what was needed from the
flash card or simply boot from the flash card like it was the system's
hard drive.
Take one, plug it into the box, the box writes the IP addresses (and
maybe the bios firmware) onto the memory, then the user unplugs the
memory from the box and plugs it into the card. Then plug the card
into the computer. Something designed for end-users to plug-unplug
without static zapping or bending pins. What about the memory cards
a lot of digital cameras use?
They are just getting smaller, but they are basically the same.
Do those have a RAM memory > type interface (not PATA/SATA/SCSI SSD
disk type interface) that a CPU could boot from directly?
They still emulate IDE hard drives. I note that SATA flash cards are
just starting to come onto the market. The main advantage is that they
have a smaller number pins in the socket.
And not cost too much? If so we could use the same slot to hold the
firmware on the Ethervideo box.
No, firmware needs to be on the other type of flash memory (NOR) that
can address individual bytes like SRAM. Flash cards (NAND) can only
address blocks of data.
So, the best way might be to simply boot from the flash card. You could
then have a program that ran on a PC that could make the boot flash
card. Still needs to come with a standard one or you have the boot
strap problem.
--
James Tyrer
Linux (mostly) From Scratch
_______________________________________________
Open-hardware-ethervideo mailing list
[email protected]
http://lists.duskglow.com/mailman/listinfo/open-hardware-ethervideo
