IBM 5170 AT 286 bios: how to add a new HARD disk - test-drb@ccmp.vtda.org

22 Jul 2014

Am 19.07.2014 23:08, schrieb Enrico Lazzerini:
...
  I managed to find a bios for an IBM 5170 AT 286 Type1
Mainboard. It is
 here: 30aprile1989 (list here:
 http://ibm-pc.org/firmware/ibm/5170/5170.htm)
 In practice I have manually added the number of cylinders, heads, and sect
 / trk that allow the machine to recognise a disk IBM 250MB. At this point
 regularly boots DOS.
 But I wish to program these data permanently in the bios. Does anyone know
 what program to use and give me the procedure? I tried with BIOSUTL, but
 the new EPROM do not boot the machine.
 With BIOSUTL i made what follow: read actual BIOS, you can add new disk
 geometry parameters at free 47 position, then you have to recalculate bios
 checsum, then BIOSUTIL devides BIOS into EVEN and ODD file so i can finally
 program them into two 27256 150nS eprom.
 Thank you
 Enrico

Hi..

the biosutil maybe one way.  The version I use told me:

Biosutil V1.1
InfoMatrix Bios utilities for the AT BIOS.
Brad Gibson Copyright (C) 1990 by Secret Software

and I believe there's no other version.

*----------------------------------------*

Other idea

It maybee better to add a enhanced bios to your PC.

There is the xtide bios at

https://code.google.com/p/xtideuniversalbios/

The xtide bios works on most xt/at.

You can easily ad an enhanced bios if you have an free rom place in a 
network card like a ISA 3com etherlink.

As Im from germany and my english isn't as good as it should be here is 
an explanation from

http://flint.cs.yale.edu/feng/research/BIOS/BIOS-report.pdf

The IBM BIOS gains much of its versatility by being an extendable BIOS. 
That is, the full extent of the BIOS is not cast forever in the silicon 
of the single PROM chip holding the firmware. The IBM BIOS can accept 
additional code as its own into one integrated whole. Hence additional 
PROM chips containing BIOS routines can be added to the PC.
The BIOS will incorporate these new routines.
The key for making BIOS extendable is a Firmware routine that enables 
the BIOS to look for add-in code. During the boot up, BIOS code reads 
through the address range that is set aside for firmware looking for 
codes stored on add-in boards. If a valid section of code is found, the 
instructions are added to the BIOS repertory. For instance a new
interrupt routine can be added or the functions of existing routines can 
be changed.

During POST after interrupt vectors have been loaded into RAM, the
resident BIOS code instructs the computer to check its ROM memory for
the occurrence of the special  preamble bytes, that mark the beginning 
of add-in BIOS routines. The BIOS searches for these preamble bytes in 
the absolute address range 0C8000 - 0F4000.

Here the XTIDE BIOS is found and added so you can use it.

Greetings

fritz