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From: bryce@COGSCI.BERKELEY.EDU (Bryce Nesbitt)
Newsgroups: comp.sys.amiga,comp.sys.atari.st,comp.sys.m6809
Subject: Re: Re: True Multitasking, and some history lessons
Message-ID: <8706040024.AA10895@cogsci.berkeley.edu>
Date: Wed, 3-Jun-87 20:24:04 EDT
Article-I.D.: cogsci.8706040024.AA10895
Posted: Wed Jun  3 20:24:04 1987
Date-Received: Sun, 7-Jun-87 05:14:57 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 30
Summary: correction of a "fact"
Xref: mnetor comp.sys.amiga:5412 comp.sys.atari.st:3840 comp.sys.m6809:324


>The Amiga's multi-tasking OS insists on loading separate
>copies of the executable code for each process using that
>code, instead of sharing one re-entrant version like OS9
>or UNIX.

Sorry, but that is not correct.
Sharing one re-entrant version of code is quite easy, no insisting needed.
Not all programs written for the Amiga *ARE* re-entrant (or even re-usable)
simply because it's not enforced.
The RESIDENT command will make a hunk of code "resident".  (very obscure loader
joke intended)
It's not automagic, but could easily be once a special "trust me, I'm reusable
and/or re-entrant" flags are added to the load format.  (See previous posting
in comp.sys.amiga about the RESIDENT compatible command)


>---------
> Thus memory can go away fast in an Amiga.

Just goes to show... if you can run 6 programs you WILL run 6 programs.

For what you get memory usage is not overly high.  However, consider how
much memory you need just for those nice graphics screens, say 16 colors/line
on a 704*464 pixel display.  Or H.A.M where you get to play with any of the
4096 all on one line?
An extra 1/2 - 12 megabytes is a much welcome addition to an Amiga.

(Of course you could use Macintosh emulation mode and drop down to a 1 bit-plane
monochrome display...)