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From: perry@well.UUCP (Perry S. Kivolowitz)
Newsgroups: net.micro.amiga
Subject: Re: ASDG recoverable ramdisk (review of same)
Message-ID: <1809@well.UUCP>
Date: Thu, 18-Sep-86 15:14:37 EDT
Article-I.D.: well.1809
Posted: Thu Sep 18 15:14:37 1986
Date-Received: Sat, 20-Sep-86 01:38:36 EDT
References: <167@picuxa.UUCP> <1530@curly.ucla-cs.ARPA>
Distribution: net
Organization: Whole Earth Lectronic Link, Sausalito, CA
Lines: 23
Summary: Only Partially True

In article <1530@curly.ucla-cs.ARPA>, cc1@locus.ucla.edu (Michael Gersten) writes:
> Wait a second...it DOESN'T use AllocMem()? Then it CANT be compatible.
> 
> Consider what happens if an interrupt routine wants to write to a file,
> and writes out to this ram disk. THERE IS NO GUARANTEE THAT AllocMem()'s
> DATA WILL BE CONSISTENT. The Ram disk looks at inconsistent data, grabs
> memory that may be returned by AllocMem, presto!
> 

While it is true that no interrupt service routine should perform an
AllocMem or FreeMem from within themselves it will never be the case
that an interrupt  service routine   will  generate new IO to my RAM
disk driver. Hence no problems.

In general though, this problem could be avoided  (if it really were
a problem) by DISABLEing and ENABLEing interrupts around memory list
management code (in addtion to forbid and permit).

The ASDG Recoverable RAM disk has been banged upon a lot and has not
show any incompatibility with 1.2 (except if you call not being able
to diskcopy df0: to vd0: an incompatibility).

Perry S. Kivolowitz