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Date:      Thu, 16 May 1996 11:42:53 -0400
From:      Garrett Wollman <wollman@lcs.mit.edu>
To:        Michael Smith <msmith@atrad.adelaide.edu.au>
Cc:        questions@FreeBSD.org
Subject:   Re: Size of the Virtual Memory Page
Message-ID:  <9605161542.AA25671@halloran-eldar.lcs.mit.edu>
In-Reply-To: <199605152309.IAA00292@genesis.atrad.adelaide.edu.au>
References:  <20894.832115521@palmer.demon.co.uk> <199605152309.IAA00292@genesis.atrad.adelaide.edu.au>

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<<On Thu, 16 May 1996 08:39:25 +0930 (CST), Michael Smith <msmith@atrad.adelaide.edu.au> said:

> BSD was written for the Vax architecture, and unless my memory's totally
> busted, the Vax imposes a fixed 4096-byte physical page size.

Ummm, no.  As others have explained, that VAX uses a 512-byte physical
page size.  As the Old Daemon Book explained in great detail, this was
so small as to be useless, hence the introduction of ``klusters'' to
make the page size be something more manageable.

> In fact, I think that even on processors where the page size is adjustable,
> almost every unix in existence uses 4K.

Ummm, no again.  On most of the processors I'm familiar with, the page
size is 8K.  4K is considered small by today's standards.  My boss is
constantly bugging me to get someone in FreeBSD to try using the page
size extensions on those processors that support them.

> Which "BSD books" are you referring to?

Presumably the Old and New Daemon Books.  I think the original
statement that prompted this discussion comes straight out of the New
Daemon Book (having just read it and remembering that it made such a
statement).

-GAWollman

--
Garrett A. Wollman   | Shashish is simple, it's discreet, it's brief. ... 
wollman@lcs.mit.edu  | Shashish is the bonding of hearts in spite of distance.
Opinions not those of| It is a bond more powerful than absence.  We like people
MIT, LCS, ANA, or NSA| who like Shashish.  - Claude McKenzie + Florent Vollant



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