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Path: utzoo!utgpu!water!watmath!clyde!rutgers!husc6!seismo!mcvax!jack
From: jack@mcvax.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: multiple applications in RAM
Message-ID: <7412@boring.cwi.nl>
Date: Wed, 10-Jun-87 03:29:10 EDT
Article-I.D.: boring.7412
Posted: Wed Jun 10 03:29:10 1987
Date-Received: Sun, 14-Jun-87 20:37:32 EDT
References: <1288@batcomputer.tn.cornell.edu>
Reply-To: jack@boring.UUCP (Jack Jansen)
Organization: AMOEBA project, CWI, Amsterdam
Lines: 26

In article <1288@batcomputer.tn.cornell.edu> braner@tcgould.tn.cornell.edu.UUCP (braner) writes:
>[]
>
>Looking forward to the 2-meg machines of next year:  1 meg is just right
>for me now, but I could use 2 megs as follows:  Say 640K for the usual
>workspace, another 640K for a "shadow" machine, and the rest (768K) for
>a reset-proof RAMdisk in High RAM.  The idea is: you press a "hot key",
>and the complete TOS environment (the first 640K) gets copied into the next
>640K.  Next time(s) you press that hot key, the two 640K pieces get
>_swapped_.  That way you can run two separate applications in RAM, instantly
>switching back and forth.  The two can communicate via the RAMdisk (which
>should also work as a disk-cache...).

This touches on a problem that I encountered (and haven't solved yet):

How can you make sure that the current program is 'idle', i.e. not doing any
disk I/O, or something similar? It seems that this is necessary for a
swapping scheme to work.

My problem is more-or-less similar: I have an interrupt driven MIDI driver,
and packets come in, requesting disk blocks. So, I want to read the block, and
send it to the machine on the other side. However, how can I make sure that
the current 'real' program isn't doing any disk I/O?
-- 
	Jack Jansen, jack@cwi.nl (or jack@mcvax.uucp)
	The shell is my oyster.