Personal computers, are designed to work with a human user. In fact, the user is a critical part of a complete computer system, especially when a personal computer is involved.
This may seem surprising, since we tend to think of computers as intelligent devices, capable of performing amazing
tasks. People also sometimes believe that computers can think
and make decisions, just like humans do. But this is not the
case. Even the most powerful supercomputers
interaction—if for no other reason than to get them started
and tell them which problems to solve (see Fig. 1
Fig. 1: A human interacting with computer.
The User's Role
When working with a personal computer; the user can take on several roles, depending on what he or she wants to accomplish:
Setting up the System. Have you ever bought a new PC? When you got it
home, you probably had to unpack it, set it up, and make sure it worked as
expected (see Fig. 2). If you want to change something about the
system (a process called configuration), you w ill likely do it yourself, whether
you want to add a new hardware device, change the way programs look on
your screen, or customize the way a program functions.
Fig. 2: Setting up a new pc.
Installing Software. Although your new computer probably came with an
operating system and some applications installed, you need to install any
other programs you want to use. This may involve loading software from a
disk or downloading it from a Web site. Either way, it is usually the user's responsibility to install programs, unless the computer is used at a school or
business. In that case, a system administrator or technician may be available
to do the job.
Running Programs. Whenever your computer is on, there are several programs
running in the background, such as the
software that runs your mouse and
printer. Such programs do not need any
user input; in fact, you may not even be
aware of them. But for the most part, if
you want to use your computer to perform a task, you need to launch and run
the software that is designed for the task.
This means installing the program, learning its tools, and working with it to
make sure it gives you the results you
Managing Files. As you have already
learned, a computer saves data in files. If
you write a letter to a friend, you can save it as a file, making it available to
open and use again later. Pictures, songs, and other kinds of data are stored
as files. But it is the user's job to manage these files, and this means setting
up a logical system for storing them on the computer. It also means knowing
when to delete or move files, or copy them to a disk for safekeeping.
Maintaining the System. System maintenance does not necessarily mean
opening the PC and fixing broken parts, as you would repair a car's engine.
But it could! In that case, you might call a qualified technician to do the job,
or roll up your sleeves and tackle it yourself. PC maintenance, however, generally means running utilities that keep the disks free of clutter and ensure
that the computer is making the best use of its resources.
Of course, there are many kinds of computers that require no human interaction, once
they have been programmed, installed, and
started up. For example, if you own a car
that was built within the last decade, it almost certainly has an on-board computer
that controls and monitors engine functions
(see Fig. 3
). Many new home appliances, such as washers and dryers, have
built-in computers that monitor water usage,
drying times, balance, and other operations.
Fig. 3: Car on-board computer diagnose.
Sophisticated userless computers operate security systems, navigation systems, communications systems, and many others.
Userless computers are typically controlled by their operating systems. In these
devices, the operating system may be installed on special memory chips rather than a disk. The operating system is programmed to perform a specific set of tasks, such as monitoring a function or
checking for a failure, and little else. These systems arc not set up for human interaction, except as needed for system configuration or maintenance.