Information Technology Reference
In-Depth Information
Stage 1:
Convert program
Figure 4.22
How a Compiler Works
A compiler translates a complete
program into a complete set of
binary instructions (Stage 1). After
this is done, the CPU can execute the
converted program in its entirety
(Stage 2).
Machine-
language
program
Computer
program
Compiler
Stage 2:
Execute program
Machine-
language
program
Program execution
Because software is such an important part of today's computer systems, issues such as soft-
ware bugs, licensing, upgrades, and global software support have received increased attention.
We highlight several major software issues and trends in this section: software bugs, copyright,
software licensing, open-source software, shareware and public domain software, multiorga-
nizational software development, software upgrades, and global software support.
Software Bugs
A software bug is a defect in a computer program that keeps it from performing as it is
designed to perform. Some software bugs are obvious and cause the program to terminate
unexpectedly. Other bugs are subtler and allow errors to creep into your work. For example,
a bug discovered in Microsoft Office Excel 2007 caused the equation 850 x 77.1 to display
that as long as people design and program hardware and software, bugs are inevitable. In
fact, according to the Pentagon and the Software Engineering Institute at Carnegie Mellon
University, there are typically 5 to 15 bugs in every 1,000 lines of code. The following list
summarizes tips for reducing the impact of software bugs.
•
Register all software so that you receive bug alerts, fixes, and patches.
•
Check the manual or read-me files for solutions to known problems.
•
Access the support area of the manufacturer's Web site for patches.
•
Install the latest software updates.
•
Before reporting a bug, make sure that you can re-create the circumstances under which
it occurs.
•
After you can re-create the bug, call the manufacturer's tech support line.
•
Avoid buying the latest release of software for several months or a year until the software
bugs have been discovered and removed.
Copyrights and Licenses
Most software products are protected by law using copyright or licensing provisions. Those
provisions can vary, however. In some cases, you are given unlimited use of software on one
or two computers. This is typical with many applications developed for personal computers.
