From: David Golden (david.golden at domain oceanfree.net)
Date: Fri 29 Jun 2001 - 11:37:20 IST
kevin lyda wrote:
>and i notice i haven't heard about
>bubble memory since then.
AFAIK, bubble memory has a niche market in miltiary-hardened
memory - cruise missile computer's memories and such. It's
low power, relatively resistant to E.M.P., but godawful slow (the "bubbles"
are magnetic domains attached to little metal chevrons - reading the
is "destructive" - involves shuffling the bubbles around in little
the bubbles off the top of a queue, and adding them again at the other
>otoh, the motorola 68k *did* offer a full set of features. the first
>sun workstation used them. but apple chose not to use those features in
>favor of a single-tasking computer. this later evolved into cooperative
>multi-tasking (baaaaad idea).
The 68000 could have memory protection, but in the form of an extra chip,
the 68851 - the Apple Lisa had one, but cost a small fortune. When no-one
bought the Lisa, Apple produced a cut-down version - the Mac...
The 68030 and above had on-board MMUs, except in the "EC" forms
(embedded controls tend not to use them).
The amiga (1985) used the 68000 for pre-emptive multitasking, but with
memory protection (via semaphore locking). I always found that my Amiga,
without true memory protection, was more stable than a windows pc,
memory protection... When I later got an amiga cpu card with an MMU, I
linux/m68k on it... :-)
Irritatingly, the incompetent CBM management (a) marketed the Amiga
as a games machine and (b) screwed up a deal with Sun which would have
Amiga A3000UX become Sun's standard low-end Unix box.
Given that the A3000 was price- and performance- competitive (and
superior for gfx and sound)
with high-end PCs of the day, history could have been bery different, if
hadn't been such complete idiots....
Any, enough ranting, now we've got linux. And we've even got
Amiga-on-linux via UAE
- and Amiga Inc. is still around, pushing their new language-independent
VM...shame it's not
true open source...
This archive was generated by hypermail 2.1.6 : Thu 06 Feb 2003 - 13:10:54 GMT