Newsgroups: comp.arch
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Paging page tables
Message-ID: <1990Jun28.182303.8352@zoo.toronto.edu>
Organization: U of Toronto Zoology
References: <3300142@m.cs.uiuc.edu>
Date: Thu, 28 Jun 90 18:23:03 GMT

In article <3300142@m.cs.uiuc.edu> march@m.cs.uiuc.edu writes:
>While reading Hennessey and Patterson (p. 437), they mention the fact
>that page tables entries are often paged themselves (with the operative
>word being often).  Now to me, paging you're means of address translation 
>makes no sense...

Unfortunately, it makes a great deal of sense, because the PTEs for a
very large process can chew up a lot of memory all by themselves.  All
it means is that you need a smaller set of PTEs to describe where the
main PTEs are, layering one address-translation mechanism on top of
another.  This is done pretty routinely.
-- 
"Either NFS must be scrapped or NFS    | Henry Spencer at U of Toronto Zoology
must be changed."      -John Osterhout |  henry@zoo.toronto.edu   utzoo!henry