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From: peirce@claris.com (Michael Peirce)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Need info on multitasking capabilities on the mac
Message-ID: <10702@claris.com>
Date: 28 Nov 89 22:29:17 GMT
References: <6391@tank.uchicago.edu> <9072@hoptoad.uucp> <17247@dartvax.Dartmouth.EDU> <9080@hoptoad.uucp> <1250@smurf.ira.uka.de>
Reply-To: peirce@claris.com (Michael Peirce)
Organization: Claris Corporation, Santa Clara CA
Lines: 43

In article <1250@smurf.ira.uka.de> urlichs@smurf.ira.uka.de (Matthias Urlichs) writes:
>In comp.sys.mac.programmer tim@hoptoad.UUCP (Tim Maroney) writes:
>< In article <17247@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu
>< (Earle R. Horton) writes:
>< 
>< I thought that MultiFinder would refuse to context switch if the file
>< or device system had any pending asynchronous requests.  But maybe I'm
>< thinking of an earlier incarnation.  It's fairly painful to write a
>< complete protocol scheduled from completion routines, but it can be
>< done.
>< 
>MF currently checks if the file manager is busy. The device manager is not
>checked. So the file I/O requests occur on top of whatever application may be
>running at the moment. No problem (but check if you have enough room on the
>stack!)
>I would not describe running a protocol from completion routines as painful.
>It's more like a lot of typing. (I ought to know :-) -- my soon-to-be-released
>AppleShare-compatible server works that way.)
>-- 
>Matthias Urlichs

I agree with Matthias, setting up a protocol that only depends on completion
routines isn't really all that painful.  You just have to understand how to
program using state machines.

Public Folder uses this model - everything done on the server side is 100%
completion routines.  It just sits there waiting for an incoming request,
then hangs a read (say), then waits for it to complete, then sends it back,
etc...  [think about it, there's no App around for PF to be a part of!]

Of course, PF is using ATP and the file system, but serial i/o should work
the same. [actually you have to roll your own timeouts with the timeMgr, but
again, not to hard to do.] 

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