Atari hard drives?

From: Ethan Dicks <erd_at_infinet.com>
Date: Thu Jun 4 08:54:50 1998

 
> <BTW, to make this on topic, when did Macs make the transition to 32-bit,
> <were all 32 bit from day one?
> < Ciao,
>
> MAC was 32bit from DAY 1. The 68000 was internally 32bit and in ithe
> various incantations 8 bit or 16 bit bus...later ones were longer bus.
> Early parts only brought out the lower 24bits of address as /back then/
> <pat pending> nobody thought 16mb wasn't enough.

Mostly. True, the 68K processor was 32 bits internal, giving rise to
a mostly 32-bit software model, but in the early days of the Mac, "clever"
programmers would take advantage of the 24-bit address bus when, for example,
building tables. To save space, one might code a table with 24 bits of
pointer and 8 bits of data. It would be safe (on a 68K Mac) to load the
entire 32 bits into an address register because the upper 8 bits (filled
with random data) would never make it off the die. When such a program is
loaded on a '020 or newer, bad things happen.

IIRC, this is what it is to be "32-bit clean" in the Mac world. The
practice stopped as soon as the MacII's came out, but it never should
have begun in the first place. The very first "Inside Macintosh", the
edition in a three-ring-binder, warned against the practice.

-ethan
Received on Thu Jun 04 1998 - 08:54:50 BST