Chapter 2 • Computer Systems 35World’s Fastest Supercomputer: Jaguar
The competition is intense to build and operate the world’s fastest supercomputer, and—for the
present—that machine is the Cray XT5 high-performance computing system known as Jaguar, deployed
by the U.S. Department of Energy at Oak Ridge National Laboratory, Tennessee. Jaguar incorporates
37,376 six-core AMD Istanbul processors and has achieved a speed of 1.75 petaflops (quadrillionfloat-
ing point operations per second) on the LINPACK benchmark program. Jaguar took over the top spot
from the IBM Roadrunner system, located at Los Alamos National Laboratory, which was the first com-
puter to crack the petaflop barrier.
The U.S. Department of Energy owns both Jaguar and Roadrunner, but the two giant supercom-
puters have vastly different purposes. Jaguar is an “open-science” tool for peer-reviewed research on a
wide range of subjects, while Roadrunner is devoted to the complex and classified evaluation of U.S.
nuclear weapons. Thus far, simulations on Jaguar have largely focused on energy technologies and
climate change resulting from global energy use. Scientists have explored such topics as the causes and
impacts of climate change, coal gasification processes to help industry design very low emission plants,
and the enzymatic breakdown of cellulose to improve biofuel production. “The early petascale results
indicate that Jaguar will continue to accelerate the Department of Energy’s mission of breakthrough
science,” said Jeff Nichols, Oak Ridge National Laboratory’s Associate Laboratory Director for
Computing and Computational Sciences.
[Based on Gonsalves, 2009b; Mansfield, 2009; and Oak Ridge National Laboratory, 2009]the control unit. Programmers today, however, do not
write their programs in machine language; they write
programs in a variety of other languages that are much
easier for humans to use—languages such as COBOL
or C++ or Java—and then these programs are translated
by the computerinto machine language. We will return
to these various programming languages shortly, but
first let’s categorize the various types of computer
software (including programming languages) that have
been created and gain an understanding of how they work
together.
To begin our look at the key elements of computer
software, let us step back from the details and view the
big picture. It is useful to divide software into two major
categories:
1.Applications software
2.Support software
Applications softwareincludes all programs written
to accomplish particular tasks for computer users.
Applications programs would include a payroll computation
program, an inventory record-keeping program, a word-
processing product, a spreadsheet product, a program to
allocate advertising expenditures, and a program producing a
summarized report for top management. Each of these
programs produces output that users need to do their jobs.
By contrast, support software(also called systems
software) does not directly produce output that users
need. Instead, support software provides a computing
environment in which it is relatively easy and efficient for
humans to work; it enables applications programs written
in a variety of languages to be carried out; and it ensures
that the computer hardware and software resources are
used efficiently. Support software is usually obtained
from computer vendors and from software development
companies.
The relationship between applications software
and support software might be more readily understood
by considering the software iceberg depicted in
Figure 2.8. The iceberg’s above-water portion is analo-
gous to applications software; both are highly visible.
Applications software directly produces results that you
as a manager require to perform your job. However,
just as the iceberg’s underwater portion keeps the top
of the iceberg above water, the support software is
absolutely essential for the applications software to pro-
duce the desired results. (Please note that the iceberg
analogy is not an accurate representation of the numbers
of applications and support programs; there are usually
many more applications programs than support pro-
grams.) Your concern as a manager will be primarily
with the applications software—the programs that are
directly relevant to your job—but you need to under-
stand the functions of the primary types of support soft-
ware to appreciate how the complete hardware/software
system works.