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From: cjp@vax135.UUCP (Charles Poirier)
Newsgroups: comp.sys.amiga
Subject: Re: Facc From ASDG
Message-ID: <1803@vax135.UUCP>
Date: Mon, 22-Jun-87 16:15:48 EDT
Article-I.D.: vax135.1803
Posted: Mon Jun 22 16:15:48 1987
Date-Received: Tue, 23-Jun-87 06:37:23 EDT
References: <4024@jade.BERKELEY.EDU>
Reply-To: cjp@vax135.UUCP (Charles Poirier)
Organization: AT&T Bell Labs, Holmdel, NJ
Lines: 28
Keywords: Time stamp
Summary: Not so fast

In article <4024@jade.BERKELEY.EDU> spencer@eris.BERKELEY.EDU (Randy Spencer) writes:
>>> What I want is a DISK cache.  Facc?  That is a DRIVE cache.  Pop out
>>> the disk for any reason, and all those lovely buffers are invalidated.
>
>Actually, the little magic cookie that lets the computer tell the difference
>between disks is the last write date on the disk.  So, if I change the
>disk in my other Amiga, the write date on the disk changes, and when I put
>it back in my first Amiga the "disk" cache would think it was a different
>disk and invalidate the old tracks (or at least not use them for this disk).

It would work if all Amigas had a consistent idea of what time it is.
But many Amigas have no clock.  (And "We don' need no Steeenkin' Setdate!"
seems to be a pretty common attitude.)

For me, I don't worry about this problem because I have no second
Amiga.  But I can understand why one might want to avoid staking the
company reputation on the impossibility of this happening.  Computing
novices could possibly get burned.  I'd be satisfied to have a
non-automatic option to (say) Facc which allows one to say "I guarantee
that Disk-named-so-and-so will never be changed if I should remove it
from the machine temporarily."  Of course, to do this one would have to
put (say) Facc somewhere in the system that knows volume names rather
than just drive numbers.  But I daresay it can be done.

-- 
	Charles Poirier   (decvax,ucbvax,ihnp4,attmail)!vax135!cjp

   "Docking complete...       Docking complete...       Docking complete..."