On Sat, 24 Nov 2012 00:06:45 +0100 Peter Stuge peter@stuge.se wrote:
Rex O'Regan wrote:
I just chose the 486 as it seems to be about the most basic that can still be used
Please clarify what you mean by that.
Maybe he had an other thing in mind but I think that you can still run Linux on a 486, and from what I remember when I programmed on such a computer it was fairly usable even to compile (simple) programs with GCC if you were not in a hurry. And you could also use DOS compilers of that area, which were a lot faster (because of the single target, no assembly pass, ...)
if there are others doing a similar thing with another class
Noone is.
Either I don't understand the question, or I don't understand the answer. I'm part of a team that designs a ~ Pentium M class motherboard for a custom purpose (telephony server / IPBX) using an Intel SoC (EP80579 -- the CPU in that thing is a Pentium M). (Info here: http://www.ohanda.org/products/xivo-ipbx-open-hardware design files there : http://git.xivo.fr/?s=xioh under GNU GPLv3+ -- the equipment has the OHANDA trademark that guarantees Open Hardware) So it is not just for fun, but it is also not a motherboard for the next state of the art processor that will only hit the market next year. And we are a very small team considering the custom blocs in our design and that we take care of both the hardware and all the BSP.
Rex O'Regan wrote:
Thanks for the input. I have only really done much software before too so this is a big jump for me.
Those numbers
Certainly for 486 and possibly already for 386 you would look for integrated chipsets, rather than using the discrete original Intel parts, or you'll most likely need to design custom hardware, e.g. in programmable logic, to sit in between.
I agree on that: finding compatible discrete parts risk to be quite hard, so you should target a System On Chip based board, or try to use programmable logic but only if you feel very adventurous and have a lot of time. Don't take my word for it and try to find if you can order some compatible discrete parts anyway, maybe it is easier than I think.
Without any hardware experience whatsoever I'd suggest that it takes three to five years of full time very fast learning with really good mentoring to design a mainboard that can run Doom.
Doom can run poorly on a 386 and starts to be pleasant on a 486. With today resources, if you make a reasonable initial part choice and rely on reference designs for all the functional blocs you will connect, you can probably get to a board of your own of that class and that does run Doom in probably less than that, depending on the amount of time you can spend on it day to day.
If it is just a hobby you'll be able to skip some time consuming and expensive points that are necessary to create a product (like certification)
Still, I agree it would be a time consuming hobby... and you should have a decent knowledge of electronic engineering or be ready to learn it to attempt it.
Cheers, Guillaume Knispel