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From: m.tiernan@pro-angmar.UUCP (Michael Tiernan)
Newsgroups: comp.sys.apple2
Subject: Re: Multitasking on a II
Message-ID: <11379.apple.net@pro-angmar>
Date: 17 Dec 90 14:56:28 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 20

In-Reply-To: message from gwyn@smoke.brl.mil

All of this is truly correct but let me add one small point, there is a flag
in ProDOS (I'm not too sure anymore if it's in any of the toolbox stuff) that
tells you when it's busy.  If you call a ProDOS write command, interrupt it,
and want to call a read (as examples) from the ISR, you check this flag, if
it's set then ProDOS is currently servicing a request and through some small
gymnastics, you put a pointer to your routine to call as soon as the
foreground process finishes thereby unbusying ProDOS.  No, the system isn't
reentrant but it is slightly intellegent.

<< MCT >>

GEnie       : M.Tiernan
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"God isn't dead, he's only missing in action."
                                             - Phil Ochs