IEEE1275

[Stefan Reinauer]

On Tue, 13 Oct 1998, Daniel Engstrom wrote:

> Some boards have 4MBit (256k byte) flash these days... And IO though one
> could use compression. The gunzip object code in linux is 14k bytes and
> the kernel compresses about 2.5:1 which means that if we total 16k
> uncompressed code we have 112k left in the PROM. If we get 2.5x as well
> it will give 280k. If we only get 2x it will still be 224k binary code.

I fear that you can't rely on this. Even many PII Systems are not equipped
with 2MBit (256kbyte) Flash chips. I also heard, that bios manufacturers
are about to lower their bios sizes again to fit into smaller chips,
because it's really not neccessary to see the cpu temperature in bios
setup for example. But on the other hand, we could say that we don't
support older boards very well in general. If you have a look at how fast
development is going at the moment, it may be acceptable because there are
no pentiums anymore until we have OpenBios ready and bootable :-)

Another idea that comes to my mind is the question for a general bios
concept. If Intel switches to ia64 at about y2k, we would only support old
and obsolete hardware if we specialize on intel ia32 architecture.

> I am more worried about NVRAM space, the standard RTC only have 64 bytes
> of which 50 bytes are general purpose. Ofcuse most board have
> RTC versions with more RAM up to 4k, but we will need compression or
> some token based system to fit the needed boot variables. 

We can say that every PC better than an 386 has at least 128bytes today.
4 or 8k versions are used in EISA boards. But as you might know, the Award
BIOS uses parts of the flash rom to save it's PnP information.

> 7: Parse NVRAM
> 8: Scan for FORTH code
> 9: Execute any FORTH code

Does anyone have an idea how much code is needed for this one?? :-)
A java bytecode interpreter comes to my mind :-)

> >> The boring part is that I believe the Open Firmware specs cost money. 
> > They are available as a book. I ordered it today :-)
> > It's ISBN Number 1-55937-426-8 IEEE Std 1275-1994: IEEE Standard for Boot
> > Firmware.
> What did they charge?
I don't know yet. They told me it would take about 6 weeks because you
don't get it in Germany and it will be about DM100-DM250, which is about
70-180US$ I think

> They have "Instruction Set Architecture Supplement"s for 
> Sparc, PPC and ARM. So if we choose that path we'll need to specify
> Open Firmware for IA-32 and the PC platform. Everything else (PCI, ISA,
> VGA, etc, seems to be specified already for CHRP I suppose.)

Hmm.. Do you have an idea where to get those "Instruction Set Architecture
Supplement"s??

Stefan.

--
"Under capitalism, man exploits man. Under Communism, it's just the opposite."
                           -- John Kenneth Galbraith