Re: The Central Mystery

Malcolm Beattie (
Fri, 25 Jul 1997 10:31:59 +0100 (BST)

Colin Plumb writes:
> > Böhme, Linux Kernel Programming, have about 40 pages on
> > memory management. Maybe this helps.
> Yes, that has been the most helpful source so far. But your explanation
> is even clearer!

If that's the book I think it is, it covers 1.2 kernels.

> > Please note that this is a Linux 2.1 description; in Linux 2.0, things
> > are slightly different.
> I know a *big* difference is that the buffer cache is used much less now.
> Basically, the buffer cache "physically tagged", by device and
> offset. The page cache is "virually tagged", indexed by inode
> and offset. It didn't used to be.

The (inode, offset) page cache has been in since 2.0 (leaving
development kernels aside). It was the 1.2 series which just had the
buffer cache. I've barely played with 2.1 kernels at all so I don't
know what slight differences between 2.0 and 2.1 he's referring to.


Malcolm Beattie <>
Unix Systems Programmer
Oxford University Computing Services