access to BIOS of DECpc - test-drb@ccmp.vtda.org

30 Oct 2004

  Hi Megan,

...
 from the mails I've got it is clear that the DECpc
320p supports just a few hard disk types and these are "hard-coded" in the
BIOS.
Worse: even the utility to access the BIOS does not support any
change of the few known hard disk types.
A few days ago was a good explanation of how a Disk Manager works,
and that's what I did. You need a floppy to boot (MS)DOS and the
OnTrack Disk Manager of the hard disk manufacturer or the OnTrack
version that accepts any brand. The first one for a specific disk
manufacturer can be found on various sites, the latter one must be
bought.
Step 1. install the new hard disk (*any* storage size, as long as
the disk fits physically :-)
Step 2. have an *empty* floppy available. Skip if you're always lucky...
Step 3. boot to DOS from the boot floppy.
Step 4. start Disk Manager (DM.EXE) from the OnTrack floppy.

DM detects the disk geometry and presents something else to the BIOS
so that the BIOS can work with the disk. Without OnTrack the BIOS does
not know how to read the disk, so better make a bootable copy on the
floppy mentioned in step 2 when OnTrack asks if you'd like to do that!

- Henk, PA8PDP.

-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
To: General Discussion: On-Topic Posts Only
Sent: 30-10-2004 8:16
Subject: RE: access to BIOS of DECpc

...
 I feel a bit silly, but it was late last night is my
excuse.
"DECpc 320P" in Google gave a link to floppy images on a COMPAQ site.
I will try them this evening, but it is good to know that the DECpc
"knows" a limited number of hard disks.  If I can 'upgrade' to some
300 Mb of the 420 Mb capacity it is still better than the 40 Mb that
I have available at this point. 
Years ago, I found out what I thought to be sufficient info to
upgrade my 320P from the 40mb drive it had, to a 120mb I had
been able to obtain... apparently type 46 and type 47 in the
BIOS are user definable.  And I guess I didn't have all the
info, or I touched the wrong area because I essentially 'bricked'
my 320p.  It no longer boots.

If you do find out how to do it reliably, I'd be interested in
trying to fix it.

                                        Megan Gentry
                                        Former RT-11 Developer

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