30 May
2000
30 May
'00
7:47 a.m.
Yes, and what several vendors recommended so their "dumb" loader prom would
work with DD media was to write the boot tracks in SD. Unfortunately I
never found one that provided a utility to do that for you, so I had to
create my own formatter with which to do that. It always bothered me to
take that approach, so I ultimately fixed my CCS box to do it "correctly" in
my view. With a 4 MHz processor it was no problem to transfer either single
or double density. The DMA was only needed if you ran a slower CPU.
However, if you needed to read the WORDSTAR software from distribution
diskettes, it was not necessary to put any low-level OS-specific materials
on the distribution medium. It didn't need to boot from MicroPro's
diskettes.
Dick
----- Original Message -----
From: John Wilson <wilson(a)dbit.dbit.com>
To: <classiccmp(a)classiccmp.org>
Sent: Tuesday, May 30, 2000 1:20 PM
Subject: Re: Defining Disk Image Dump Standard
On Tue, May 30, 2000 at 12:01:30PM -0700, Don Maslin
wrote:
on
But that is/was not always true! There were a
number of 8" CP/M systems
that used bootable DD formats, and most all 5.25" CP/M systems were in a
bootable DSDD format.
I always figured the reason for the restriction was dumb boot PROMs, which
only know how to do programmed I/O to the FDC, and 8" DD comes in too fast
for typical 8-bit CPUs of the time to handle with PIO. If the boot PROM a particular system is smart enough to set up DMA, no
need to require SD.
John Wilson
D Bit