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From: roberts@cognos.uucp (Robert Stanley)
Newsgroups: comp.sys.mac
Subject: Re: A Rather dumb question...
Message-ID: <1720@cognos.UUCP>
Date: Thu, 5-Nov-87 14:51:01 EST
Article-I.D.: cognos.1720
Posted: Thu Nov  5 14:51:01 1987
Date-Received: Sun, 8-Nov-87 07:42:20 EST
References: <1939@crash.CTS.COM>
Reply-To: roberts@cognos.UUCP (Robert Stanley)
Organization: Cognos Inc., Ottawa, Canada
Lines: 33
Summary: 4 Gigabytes and 32 bits

In article <1939@crash.CTS.COM> maddie@pnet01.UUCP writes:

>  Anyone out there know what the maximum Hard-Disk size is on the Mac before
>you have to partition? For some reason 4 gigabytes seems to pop into my head,
>can anyone tell me for certain?

I don't know the real answer, because I can't afford individual disks in the
gigabyte range :-).  However, 4 gig is 2^^32, or the largest binary integer
value (unsigned), that can be stored in a 32-bit field.  For a variety of
reasons it is moderately unlikely that a larger field will be used, nor is it
likely to matter in the reasonable future.  The question is, might it be a
smaller field?  At present, the Mac could reasonably be described as having a
24-bit architecture, at least with respect to operating system stuff.  So
saying, the lower limit would be 2^^24, or 16 meg, but we can readily see that
the actual limit is greater than this.  Who among us remembers when the
industry standard high-end disk was 29.5 Meg?

So saying, chances are good that a 32-bit field controls the number in
question, which gives 4G (unsigned) or 2G (signed).  I know, who would ever
want a signed value for maximum disk capacity, but stranger things can be
observed in any operating system...

Now, we are all agog to hear *why* you need to know.

Warning: the foregoing, while reasonable, must be considered as speculation
	 and not as fact.

Robert_S
-- 
Robert Stanley           Cognos Incorporated     S-mail: P.O. Box 9707
Voice: (613) 738-1440 (Research: there are 2!)           3755 Riverside Drive 
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