stepping machanism of Apple Disk ][ drive (was Re: Heatkit 51/4 floppies)

From: allisonp_at_world.std.com <(allisonp_at_world.std.com)>
Date: Fri Apr 9 08:11:30 1999

On Fri, 9 Apr 1999, Richard Erlacher wrote:

> Careful, now! He would have played hell trying to interleave memory
> accesses between an 8080 and the video refresh process, since its various
> cycle types were so different. It would have been worse YET with a Z-80!

It was done though. The 6845 you generally talk to it's local ram through
it not around it. The H19 terminal did the latter.

> The 6502 also allowed him to proceed with his own DOS and his OWN version of
> BASIC, without which he mightn't have gotten the strangle-hold on the
> personal-computers-in-business market. It's pretty hard to criticize his
> choices, however little I liked the result from the standpoint of seeing it
> as a tool, but his (and his partner's) decisions were definitely vindicated
> in the marketplace.

It proved software was more important than hardware. The best cpu with no
software was still nothing. The z80 was maybe the best at the moment but
the 6502 was as versitile and plenty fast enough to make up for it's
limitations.

Likewise the trs 80 would prove lowercase and some more speed were very
desireable (based on the two most common mods!).

Allison
Received on Fri Apr 09 1999 - 08:11:30 BST