BSD virtual memory mngmt algorithm. Was: Performance Tuning Ultrix 4.1

[Chris Jankowski]

(I am cross posting this to comp.arch as it seems to be a general 
operating system issue.)

In article <1991Apr30.160331.16215 at milton.u.washington.edu> 
corey at milton.u.washington.edu (Corey Satten) describes certain
behaviour of Ultrix 4.? virtual memory subsystem and the way to
tune the system. 
I think that he also suggests that Ultrix 4.? uses pretty much
standard BSD 4.3 algorithms in this area.

This raises interesting questions:

1. Did other vendors (who derived their commercial U*X offerings from 
BSD) modify or tune the virtual memory subsystem to significant
extent perhaps providing new nifty algorithms?

2. What does it looks like for ATT System V rel. 3 and 4?
Do they have very different virtual memory management?

3. What is the state of the art in this area considering vastly
increased demands on the virtual memory subsystem imposed by
X.11, RDBMS, transaction processing and the like applications?

4. Do other operating systems using virtual memory approach differ
much in the way of the algorithms used for virtual memory management?

Enquiring minds would like to know.
 
 +-+-+-+-+-+-+-+ Chris Jankowski - Open Systems Eng.- chris at ubeaut.enet.dec.com
 |d|i|g|i|t|a|l| Digital Equipment Corporation (Australia)   tel.+61 3 655 5622
 +-+-+-+-+-+-+-+ 45 Exibition St, Melbourne 3000, AUSTRALIA  fax +61 3 655 5655

 ... and in the last 50 years ... there has never been a famine in a country 
 with a free press         - Lawrence Summers - chief economist - World Bank