Defining Disk Image Dump Standard

From: John Wilson <wilson_at_dbit.dbit.com>
Date: Tue May 30 14:20:33 2000

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 - 14:20:33 BST