From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Tue, 29 Jul 2008 12:28:34 -0400
From: Venkatesh Srinivas <me@acm.jhu.edu>
To: 9fans@9fans.net
Message-ID: <20080729162834.GC31092@satori.no-ip.org>
References: <20080717142135.539A31E8C1C@holo.morphisms.net>
	<20080729085214.GA3072@nibiru.local>
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Subject: Re: [9fans] mmap
Topicbox-Message-UUID: f3f23b16-ead3-11e9-9d60-3106f5b1d025

As far as interfaces go, mmap() is pretty tragic - the underlying
translation structures can express more interesting things, some of
which are even worth doing.

There have even been OSes that let userland apps play with their address
spaces in far more interesting ways - KeyKOS and EROS come to mind. And
they were even fast, or something.

In a system like Plan 9, where your file servers are on the other side
of a 9P link, this mmap thing seems dubious. If what you want is the
convenience that you get from having all the bytes in memory, reading
them all in wouldn't be too hard. mmap()s magic really arises when you
have a page-cache-like-thing.

--vs