Subject: Re: CCL:Top PC vs. Unix

From: Rick Venable <[email-masked]>
Date: Sun, 22 Mar 1998 13:43:15 -0500 (EST)

On Sun, 22 Mar 1998, Attila Aranyos wrote:
> Does anyone know how fast (or slow :)) is a top PC with all you can get now
> (P-II 333 MhZ (may be dual) and tip-top HD contorller ) compared with a
> Unix workstation?

The real issue is the price/performance ratio; you could probably buy a
Unix workstation that might out-perform a top PC, but you would probably
spend a good deal more money.  The disadvantage of the PC approach
(assuming Linux) is that you really have to have someone around who can
handle the sysadmin stuff, but it's not much different from dealing with
IRIX, HP-UX, AIX, etc.  Note that current mother boards will be rate
limiting for *parallel* usage of dual 333 MHz processors, and the I/O
subsystem will be rate limiting for larger calculations that require the
continuous use of the swap partition on the hard disk.  If the 333 MHz
costs a lot more, I'd buy slightly slower processors and spend the savings
on more memory. 

Linux on a PC is a very cost-effective and viable platform for many
computational chemistry codes; with an add-on GL board, it can be an
alternative to an SGI in some cases, especially where source code is
available.  There are good Fortran compilers available, both free (g77 and
f2c/gcc) and commercial (AbSoft).  By "good", I mean that MD and QM codes
written to (mostly) the Fortran 77 standard compile, and produce
executables which run efficiently and give correct (or equivalent)
answers. 

--
Rick Venable                  =====\     |=|    "Eschew Obfuscation"
FDA/CBER Biophysics Lab       |____/     |=|
Bethesda, MD  U.S.A.          |   \    / |=|  ( Not an official statement or
[email-masked]  |    \  /  |=|    position of the FDA; for that,
http://nmr1.cber.nih.gov/           \/   |=|    see   http://www.fda.gov  )
http://www.erols.com/rvenable