more than one operation simultaneously. Workstations will feature at least
64 MB (megabytes) of RAM, built - in network support, and a graphical user
interface (GUI). More sophisticated instrumentation such as high - fi eld NMR
require workstations for data acquisition, manipulation, and display of one - ,
two - , and three - dimensional NMR spectra. Low - end workstations may be
powerful PCs and Macs, while high - end models are available from companies
such as Silicon Graphics, Sun, Hewlett Packard, IBM, and so on. More sophis-
ticated graphics, molecular modeling, molecular design, and analysis software
such as SYBYL TM , SYBYL CSCORE TM , and UNITY TM components sold by
Tripos, Inc. and discussed below in Section 4.5 require workstation capability
for full usability.
Minicomputers are medium - sized machines usually having multiple users.
They have one or more CPUs working together and large amounts of both
RAM and storage. The OS will be some form of the Unix operating system.
Most of the time, the chemist will interface through a PC or workstation with
the minicomputer acting as a server. Manufacturers of these machines are Sun,
Silicon Graphics, or Hewlett Packard, among others.
Mainframes are large computers comprised of a cluster of tightly coupled
machines or having multiple processors. These units will often be set up for
specifi c applications as database servers, or for handling calculations such
as those generated by quantum mechanics - based computational chemistry
methods.
Supercomputers often have hundreds of linked high - speed processors and
very large memories. Very large calculations are performed across many pro-
cessors at once, and the so - called parallel processing is very effi cient for
manipulating large mathematical data arrays. Supercomputers often have a
minicomputer front end providing the user interface, and only the largest
computing jobs are actually run on the supercomputer. These machines are
produced by IBM, Intel, Cray Research, Silicon Graphics, Fujitsu, NEC, and
Hitachi companies, among others.
A relatively new computer architecture called cluster or parallel computing
is comprised of groups of small machines hooked together. The clusters can
be assembled from off - the - shelf PCs, making their cost low. Chemists are
particularly interested because they are useful for increasingly computing -
intensive modeling and simulation projects. Chemists are engaged, alongside
computing experts, in modifying chemistry software but also designing general
tools to make clusters and their ilk run better. Bioinformatic researchers are
interested because of the huge computing needs brought about by develop-
ments in genetics and proteomics. A recent book; Parallel Computing for
Bioinformatics and Computational Biology , edited by Albert Zomaya, will be
of interest to those in this fi eld.^2
Computer clusters contain a number of processors put together on a moth-
erboard into a unit known as a node. The nodes are then hooked together with
other boards via high - speed communications networks. Nodes can be hard-
wired into supercomputers produced by companies like IBM and Compaq or
COMPUTER HARDWARE 159