"CP/M compatible" vs. "MS-DOS Compatible" machines?
Roy J. Tellason
rtellason at verizon.net
Tue Feb 5 01:20:29 CST 2008
On Monday 04 February 2008 14:48, Chuck Guzis wrote:
> I wanted to add a "put that diskette back" alarm to my CP/M
> implementation when there were files opened for writing
> (one needn't even turn on the drive motor--just periodically sample the
> write-protect status; a diskette being inserted or removed will toggle it a
> couple of times).
I had some drives that also had a switch that would go active when the door
was opened, I think originally intended for the Wang PC or similar, they're
FH 5.25" but worked as well as anything else with the Bigboard II when I had
them hooked up to it.
> I'd already done it for DX-85M
> and it reduced our diskette file corruption problems to nearly zero.
> That "R/O error" diagnostic from CP/M was unreliable at best and nearly
> useless even when it worked.
> It was then that I discovered that CP/M made no attempt to track open
> files and indeed, the behavior of many programs depended on this.
It wasn't really much of an OS, compared to a lot of what else was out there.
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