Extracting CDOS and CP/M) files
M H Stein
dm561 at torfree.net
Fri Oct 12 17:15:22 CDT 2007
Date: Fri, 12 Oct 2007 16:43:03 -0400
From: "Roy J. Tellason" <rtellason at verizon.net>
Subject: Re: Extracting CDOS and CP/M) files
On Friday 12 October 2007 03:23, M H Stein wrote:
> Want to copy your SDSS 8" disk to a DDDS 5" one? No problem.
> Friend or business partner has some data on SDSS 5" disks that you
> want on DDDS 8"? Just pop in the disks and copy away; add some
> software and you can even copy to/from MS-DOS disks if you must.
> Run Z80 CDOS/CP/M Wordstar on your 68000 Cromix+ CS-400?
> No sweat (although a different issue). Process your old CDOS data
> files with your UNIX software? Not much harder.
> It all just looks different from today's PC-centric perspective.
So what sort of hardware does it take to be able to do stuff like that?
I know my Bigboard II has both sizes of floppy drive connectors, though I
think there's a jumper change involved to deal with different data rates
IIRC. And there might be some potential for that board that's in my
Cromemco, as well.
I'm sure that a lot of my CP/M boxes have controller chips that are much more
capable than the pc-centric stuff is, too.
And how would the OS have to handle this? Some serious BIOS hacking?
The simple answer for a Cromemco box is a minimum configuration of a DPU,
16/64FDC, 128KB of memory and optionally a hard disk & controller.
(You'd need somewhat more to run UNIX).
AFAIK, as far as Cromemco systems go (assuming a 16FDC controller or later,
and soft-sector disks):
CDOS can read/write any one of the 8 (10?)possible CDOS formats and 8"SSSD
CP/M (which, essentially being the first floppy "standard", was a more-or-less
universal distribution medium for software such as WordStar, SuperCalc etc).
Third-party software was available to handle other formats, and there were also
custom versions of CP/M configured for a Z80 Cromemco.
CDOS itself is a clone of an early 1.x version of CP/M, which Cromemco licenced
from DRI and enhanced somewhat with some additional calls, and it can run most
CP/M software (at least early pre-2.x versions).
Any version of Cromix (Cromemco's early Z80 and 68000 pseudo-UNIX) can
read/write any version of CDOS or Cromix disk (floppies, that is; hard disks are a
Third-party software (e.g. CsCopy) can read/write MSDOS disks but requires Cromix+
(and a 680x0 CPU) which was the current Cromix version when the PC became
Cromix+ and UNIX both read/write UNIX format disks; anything else that Cromix+
could handle was transferred to UNIX via a shared HD partition.
Anything else would indeed require some custom programming; the FDC controller
cards were reasonably well documented.
If the main CPU was a 680x0 instead of a Z80 then Z80 & CP/M software was run
either on a dual (Z80/68000) DPU card or, if there was only a 680x0 CPU then it
was run on the Z80 on an I/O card such as the IOP I/O processor or the Octart
8-port RS-232 card, if available.
Their first hard disks were 11MB 8" IMI drives using a WDI controller; they were
superseded by 5 & 20 MB 5" IMI drives requiring a WDI-II. Then came MFM disks
using an STDC controller and SMD drives & controller, and finally ESDI and SCSI
drives using the ESDC controller.
The floppy controller also supported the small tape drives while the larger tapes
required the ESDC controller, and there was also a controller and OS support
for 9-track mag tape.
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