Re: Linux VM system vs. BSD ditto

From: Gérard Roudier (
Date: Wed May 24 2000 - 16:32:07 EST

On Wed, 24 May 2000, Gustav Kristoffer Ek wrote:

> I'm keep hearing that the BSD-way of doing VM system is faster when memory
> is tight than the Linux-way. I is said that the reason is that linux uses
> a one-hand algorithm and bsd a two-hand. What is this about? Any good
> links that cleares this out?

Linux-2.2 is using the 'one-hand' but 2.3 uses a single LRU.
Current fine BSD O/Ses seem to use the active/inactive queue algorithm
that may well come from Mach (historians should confirm).

The 'one hand' algorithm made full sense at the time memory size were not
that large. IIRC, the 'two hand' algorithm has been invented by BSD guys
when memory size increased, for the reason it took too long to do a
revolution of the map. This let me think that the 'two-hand' algorithm was
rather an hack than a really superior algorithm. Btw, this happened may-be
10-15 years ago, so this may well be just off-topic nowadays. :)


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