Re: Negative Open Counts (was Re: IEEE libraries)

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#9772

From: Peter da Silva
Date: Tue, 13 Sep 1988 11:00

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In article <39822@linus.UUCP>, eachus@mitre-bedford.ARPA (Robert Eachus) writes:
>      When a  library is opened  by a task, if the (open) count is
>      non-negative, increment it by one.  When a library is closed
>      decrement  the count by one.  Libraries may only be unloaded
>      when the count is zero.

Not good enough:

	Task A opens guru.device.
	Task B opens guru.device.
	Task B closes guru.device.
	Task B closes guru.device again.
	Memory gets low, guru.device is purged.
	Task A accesses guru.device. GURU MEDITATION 00000004.00C50899

The open count never went negative.

The only way to do this right is to track opens on a per-task basis. This
requires long-term uniqueness of task ids which the current setup doesn't
allow for: that message port might end up being created in the same place
as the old one.

The best way to implement this would be general resource tracking. 1.5? 2.0?
-- 
		Peter da Silva  `-_-'  peter@sugar.uu.net
		 Have you hugged  U  your wolf today?

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Message-ID: <2620@sugar.uu.net>

Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!tness7!tness1!sugar!peter

References: <1356@percival.UUCP> <b03Kac9bnd10108qAIk@amdahl.uts.amdahl.com> <39822@linus.UUCP>

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!tness7!tness1!sugar!peter
From: peter@sugar.uu.net (Peter da Silva)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Negative Open Counts (was Re: IEEE libraries)
Keywords: open counts
Message-ID: <2620@sugar.uu.net>
Date: 13 Sep 88 11:00:59 GMT
References: <1356@percival.UUCP> <b03Kac9bnd10108qAIk@amdahl.uts.amdahl.com> <39822@linus.UUCP>
Distribution: na
Organization: Sugar Land Unix - Houston, TX
Lines: 26

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