Microsoft Office Tutorials and References
In Depth Information
Computer Software
Computer Software
As you have already learned, software is defi ned as the instructions and associated data
that direct the computer to accomplish a task. Sometimes the term software refers to a
single program, but often the term refers to a collection of programs and data that are
packaged together. For example, the Microsoft Offi ce 2010 software includes programs
that help you draw graphics, create documents, and make calculations. The software
includes some data, such as a thesaurus of words and their synonyms.
Software can be divided into two major categories: system software and
application software. System software helps the computer carry out its basic operating tasks.
Application software helps the user carry out a variety of specifi c tasks.
System Software
System software manages the fundamental operations of your computer, such as loading
programs and data into memory, executing programs, saving data to disks, displaying
information on the monitor, and transmitting data through a port to a peripheral device.
There are four types of system software: operating systems, utilities, device drivers, and
programming languages.
Recall that an operating system controls basic input and output, allocates system
resources, manages storage space, maintains security, and detects equipment failure. You
already learned the importance of data communications from a standalone computer and
from a workstation to other users on a network. The fl ow of data from the microprocessor
to memory to peripherals and back again is called basic I/O , or input/output . The
operating system controls this fl ow of data just as an air-traffi c controller manages airport traffi c.
A system resource is any part of the computer system, including memory, storage
devices, and the microprocessor, that can be used by a computer program. The operating
system allocates system resources so programs run properly. Computers are capable of
multitasking —starting and running more than one program at a time—because the
operating system is allocating memory and processing time to make this possible. An
example of multitasking is producing a document in your word processing program while
you check a resource on the Internet. Both the word processing program and the Web
browsing program are allowed to use parts of the computer’s resources, so you can look
at the resource periodically while you are writing your document. The operating system
is also responsible for managing the fi les on your storage devices. Not only does it open
and save fi les, but it also keeps track of every part of every fi le for you and lets you know
if any part is missing. This activity is like a fi ling clerk who puts fi les away when they are
not being used, and gets them for you when you need them again.
The operating system’s responsibility to maintain security might include requiring a
username and password or checking the computer for virus infection. Finally, the
operating system guards against equipment failure. Each electronic circuit is checked
periodically, and the moment a problem is detected, the user is notifi ed with a warning message
on the screen.
Microsoft Windows, used on many PCs, and the Mac OS, used exclusively on
Macintosh computers, are referred to as operating environments because they provide a
graphical user interface GUI , pronounced “goo-ey”) that acts as a liaison between the (
user and all of the computer’s hardware and software. In addition to the operating system,
Windows and the Mac OS also include utilities, device drivers, and some application
programs that perform common tasks. Figure 26 shows the starting screen for Microsoft
Windows 7.
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