[OpenBIOS] Intel holding back information
smith at elvis.rowan.edu
Sun Aug 8 16:01:23 CEST 1999
I am new at bios programming. I have written several asm
programs that use int 13 and other bios and dos functions. I am really
interested in writting my own bios. I was wondering if anybody had any
documentation or instructions on how to get all the code from your bios. I
know about the cmos chip, but can you get all the information from cmos or
do you have to get it from somewhere else. I know a little about low level
functions and port i/o but i need some help.
From: David J. Coffin <dcoffin at shore.net>
To: Niklas Ekström <t97nek at student.tdb.uu.se>
Cc: openbios at elvis.informatik.uni-freiburg.de
<openbios at elvis.informatik.uni-freiburg.de>
Date: Saturday, August 07, 1999 5:06 PM
Subject: Re: [OpenBIOS] Intel holding back information
> You cannot get a DRAM-sizing algorithm from Intel with-
>out signing an NDA, and the NDA forbids you to share your
>source code without Intel's written permission.
> This is necessary to protect Intel's "competitive ad-
>vantage", even for a chipset that was discontinued two years
> VIA Technologies publishes their DRAM-sizing algorithms
>without restriction. The VIA 580VP chipset matches the Intel
>430FX almost bit-for-bit, so this is a good place to start.
> For an example of actual code, disassemble an Award,
>AMI, or Phoenix BIOS. Don't read the BIOS from shadow RAM;
>copy it off the chip or find it on the web. The DRAM- and
>cache-sizing code are easy to find, because most everything
>else is compressed to resemble random noise.
> There is no way for the BIOS writer to conceal Intel's
>secrets. DRAM-sizing code must run directly off the flash
>chip, so it can never be compressed or encrypted.
> Dave Coffin 8/7/99
>On Fri, Aug 06, 1999 at 01:16:27AM +0200, Niklas Ekström wrote:
>> I have been in contact with Intel about obtaining the BIOS specifications
>> for various chipsets (in particular the 430FX which is the chipset of my
>> testing environment), but they seem very reluctant to give them away. I
>> guess it might depend on that a) you normally have to sign a
>> Non-Disclosure Agreement to obtain them (which doesn't go well with the
>> fact that I will make the source for the BIOS publicly available) and
>> possibly b) that I'm a private person and not a well recogized BIOS
>> manufacturing company.
>> Does anyone have a good suggestion as how to solve this issue? I think
>> this is quite a major issue. Even though I think I have a clue on how to
>> do most things (detecting memory size and type (FPM/EDO)), I also believe
>> there are some things that you would actually need the BIOS specification
>> for (atleast so I don't have to _guess_ how to do some things).
>> I believe some of you here (professional BIOS programmers) have read
>> specifications. Can you give any hint to how much information these
>> specifications contain and how vital that information is? Also, is it
>> possible to obtain that information for any other source?
>> / Niklas
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