"As of the middle of 2001, the world's fastest computer
can perform, on average, about five trillion floating point
operations per second, or 5 teraflops. The machine that ranks 500th
averages about 55 gigaflops. In general, such top-tier computing
power is quite expensive and unavailable (see Resources later in
this article). However, in 1994, Thomas Sterling and Don Becker
established that there is a way to use common and affordable
hardware plus Linux to bring together the computing power of
clusters of relatively smaller machines. The result, called a
Beowulf cluster, can inexpensively emulate the computing power of
the bottom ranks of the top machines.
The Beowulf strategy aims at minimizing computation time. A CPU
operating under MS DOS can sequentially process only one program's
instructions. We would like to reduce this baseline. In the case of
one CPU running under Linux or NT, it is possible for multiple
programs to share the CPU's resources, but all things being equal
-- like word size and disk access speed -- no program processes any
faster than it would under MS DOS. Moreover, in the case of
Symmetric Multi-Processing (SMP) where two or four CPUs are running
under Linux or NT, each processing multiple programs, it still
takes approximately the same amount of time to process any single
program.
Now, one option for reducing the processing time of a program is
to divide it into independent sub-tasks that can be processed by
different CPUs. When the results of these sub-tasks are available,
they can be returned to one of the processors for final processing.
Clearly, this reduces the processing time for a given program.
Multi-threaded programs running under Linux on a motherboard with
two or four CPUs illustrate this fact."
