PC Farms for Offline Event Reconstruction at Fermilab

Paper: 444
Session: G (talk)
Speaker: Wolbers, Stephen, Fermilab, Batavia
Keywords: off-the-shelf products, commodity computing, parallelization, PC operating systems, large systems

PC Farms for Offline Event
Reconstruction at Fermilab

A. Beretvas, P.T. Chang, F. Donno, M. Fischler, J. Fromm, D. Holmgren,
Y.C. Liu, K. Stox, K. Thayalan, W. Wolbers, P. Yeh, G.P. Yeh
Fermilab and Academia Sinica, Taipei, Taiwan

A set of 8 PC's has been purchased by Fermilab for the purpose of
investigating the utility of these machines for various offline tasks
in high energy physics. Six of the machines are Pentium based (166
MHz), four with 32 MB of system memory and two with 64 MB of memory.
The other two systems are Pentium-Pro based (200 MHz), each with 32 MB
of memory. Two of the systems have IDE disk interfaces, and the
others have SCSI (ultra,wide) interfaces. All of the systems use the
PCI bus. The machines are interconnected via a fast ethernet
(100Base-T) network.

The PC farm was purchased to allow us to explore the use of PC
computing hardware for HEP computing problems. Issues that are being
investigated include the operating system, utilities and software
products, and the possibility of building and testing larger systems
for full offline event reconstruction, including parallel processing.

Most of the work that has been done so far has concentrated on the
use of LINUX, a free UNIX-like operating system. The LINUX kernel was
developed by Linus Torvalds and most of the other LINUX system
infrastructure (libraries, compilers, utilities) comes directly from
the Free Software Foundation (GNU). The Slackware distribution
(version 3.1) was used to install LINUX on the systems. The major
kernel version is 2.0. Currently two systems also have Free BSD
installed (version 2.1.5 and 3.0). We will also investigate NT

Much of the software that physicists use as part of everyday work
has been ported to LINUX. These include TeX, editors, cernlib, the
Fermilab environment, etc. The porting has in general been
straightforward (many times already done by someone else) and no major
problems have been found.

To port major HEP codes to the farm requires a way to compile
codes. An investigation has been made of the f2c package, the g77
compiler from GNU, the Absoft fortran compiler and the Microway
fortran compiler. As a side-investigation, we have used these fortran
compilers and translators to measure the speed of the PC's and compare
these to the speed of common UNIX systems at Fermilab.

Finally, full HEP offline codes are being ported to the PC. The
goal is to produce a full HEP package running under LINUX, using
the parallel processing package cps. This will be a nice
demonstration of the capabilities of the system and give a feel for
the potential of the system for HEP event processing. We will report
on progress towards porting the entire CDF offline package to the PC
farms running LINUX.