CP/M Hard Disc BIOS

discussion of beeb/electron applications, languages, utils and educational s/w
Post Reply
Coeus
Posts: 1083
Joined: Mon Jul 25, 2016 11:05 am
Contact:

CP/M Hard Disc BIOS

Post by Coeus » Tue Jul 10, 2018 6:31 pm

Questions, probably for JGH: Disc http://mdfs.net/Mirror/Image/AcornCPM/JGHCPM1.zip is a CP/M bootable disc with a hard disc BIOS.

1. Does this make any assumptions about the disc interface, i.e. SCSI or IDE.
2. Does it need reserved tracks on the disc or does it turn an ADFS file into a virtual hard disc?
3. Can CP/M be booted from a hard disc this way?

User avatar
jgharston
Posts: 3249
Joined: Thu Sep 24, 2009 11:22 am
Location: Whitby/Sheffield
Contact:

Re: CP/M Hard Disc BIOS

Post by jgharston » Tue Jul 10, 2018 10:21 pm

Coeus wrote:
Tue Jul 10, 2018 6:31 pm
Questions, probably for JGH: Disc http://mdfs.net/Mirror/Image/AcornCPM/JGHCPM1.zip is a CP/M bootable disc with a hard disc BIOS.
1. Does this make any assumptions about the disc interface, i.e. SCSI or IDE.
No, it just accesses a disk image through the normal OPEN/GBPB/CLOSE interface.
Coeus wrote:
Tue Jul 10, 2018 6:31 pm
2. Does it need reserved tracks on the disc or does it turn an ADFS file into a virtual hard disc?
Drive C: is stored as a disk image on the filing system you specify in the file you specify. The linked-to disk image is configured to use adfs:$.CPMFILE. You can change what disk image file to use with the supplied MOUNT.COM utility.
Coeus wrote:
Tue Jul 10, 2018 6:31 pm
3. Can CP/M be booted from a hard disc this way?
No, Acorn CP/M is hard-wired to boot from drive 0. You need to boot from a system floppy with HDBIOS installed on it, and then the hard drive becomes active. There's a way to right a sideways ROM to supply the boot BIOS, but I've never got it working properly.

See also CPM/Acorn/HardDrive.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

Post Reply