Accessing IBM PS/1 BIOS
Posted on 1998-02-16
A relative has got hold of an old IBM PS/1 and has asked me to help resolve a problem with it.
It's been running Windows 3.1 quite happily, but for no apparent reason a few weeks ago it refused to allow the program to work any more, and instead gave a message about requiring "himem.sys" to be loaded in the config.sys file.
In addition, the machine now boots to a screen divided into four giving options to run DOS, Works (installed on the machine), "your programs" or the guided tour/help facility.
Among the choices offered when you enter one of these four options is to go to the DOS prompt, which I have done and found that himem.sys is correctly called by the config.sys on C: drive and is in the right place.
HOWEVER, it appears that there is a D: drive in the form of a ROM chip which has its own system files and I suspect that these are now being called first, ahead of the C: files. The D: config.sys file has no mention of himem.sys.
I've asked the company that supplied the machine (MANY years ago) for help, and was advised to get into the Bios to check the boot sequence. I can't do that. The method I was told to use was to hold down the F1 key while switching on, but this doesn't work. Nor does holding down escape.
It was also suggested that I boot with the MS DOS disk 1 in drive A, but the machine refuses to boot from this drive.
I suspect that this machine has had it, but if anyone can suggest how I can over-ride the ROM chip, I'd be grateful. I opened up the case and had a look for an easily removable chip, but all I could find was something that appeared to be providing about 128k of RAM!