NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/comp/unix/aix/11719

Text File | 1992-11-18 | 1.9 KB | 40 lines

Newsgroups: comp.unix.aix
Path: sparky!uunet!spool.mu.edu!caen!batcomputer!ghost.dsi.unimi.it!univ-lyon1.fr!chx400!aragorn.unibe.ch!iacrs2!schuetz
From: [e-mail] (Martin Schuetz)
Subject: Re: RS6000 almost stops with heavy disk access.
Message-ID: <[e-mail]>
Sender: schuetz@iacrs2 (Martin Schuetz)
Reply-To: [e-mail]
Organization: University of Berne, Switzerland
References:  <[e-mail]>
Date: Thu, 19 Nov 1992 09:02:37 GMT
Lines: 27

In article <[e-mail]>, [e-mail] (Joao Luis Silva Damas) writes:
|> Hi,
|> we have two rs6000 (a 320H and 340) being used by different kinds of users.
|> Some of them do large molecular calculations which create HUGE (600-700 MB) tem
|> porary files for the molecular integrals. When their program begins writing the
|> se huge files and then reading them as needed, our machines almost stop and oth
|> er users are almost unable to use the system. The slowness means 30-60 sec to l
|> ogon, 1 minute for X windows to create a new window, a long time for even an ls
|> , etc. Most other users do a lot of editing so they actually need better respon
|> se time from the machine.
|> Is there anyway to correct this situation (besides killing those huge calculati
|> ons, of course)?
|> Thanks for your answers,
|>                       Joao Damas

1) Consider installation of NQS with fixed priority patch
   (obtainable e.g. from this site)
2) If these large, molecular calculations are Gaussian 9x Hartree-Fock
   ab-initio calculations, use the direct SCF method. This reduces
    disk-access considerably and is faster on the rs6k.

Hope that helps...
--
Martin Schuetz                              Phone: [phone]
Institute for Physical Chemistry            FAX:   [phone]
University of Berne
Switzerland                                 [e-mail]