Defining Disk Image Dump Standard

From: Richard Erlacher <richard_at_idcomm.com>
Date: Tue May 30 14:47:51 2000

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_at_dbit.dbit.com>
To: <classiccmp_at_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:
> >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
on
> a particular system is smart enough to set up DMA, no need to require SD.
>
> John Wilson
> D Bit
>
Received on Tue May 30 2000 - 14:47:51 BST