Definitions
A computer system
consists of two major elements: hardware and software. Computer hardware is
the collection of all the parts you can physically touch. Computer software,
on the other hand, is not something you can touch. Software is a set of
instructions for a computer to perform specific operations. You need both
hardware and software for a computer system to work.
Some hardware
components are easy to recognize, such as the computer case, keyboard, and
monitor. However, there are many different types of hardware components. In
this lesson, you will learn how to recognize the different components and what
they do.
Types of
Computers
Before looking at the
various components, it is useful to distinguish between two different types of
computers: desktop computers and laptop computers. A desktop computer consists
of a computer case and a separate monitor, keyboard, and mouse. As the name
suggests, this type of computer is typically placed on a desk and is not very
portable.
Typical desktop computer with a separate
computer case, monitor, keyboard, and mouse
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A laptop
computer has the same components but integrated into a single,
portable unit.
Typical laptop computer with integrated
hardware components
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While these two types
of computers look quite different, they have the same general hardware
components.
Hardware
Components
Let's start with
the computer case. This is the metal enclosure that contains many
of the other hardware components. It comes in various shapes and sizes, but a
typical tower model is between 15-25 inches high. Want to know
what's inside? Okay, go get a screwdriver and let's open it up. Seriously, if
you are really into computers, the best way to learn is to actually get
hands-on. To save us some time, however, have a look at this desktop computer
case. A computer enthusiast replaced the metal side panel with a transparent
one, so we can have a look inside.
Although that photo
looks pretty cool, it is a bit hard to recognize the individual components,
especially with all the connecting wires running through it. This figure shows
a more schematic version of a desktop computer, which makes it easier to point
out the essential hardware components.
The computer case
contains a power supply unit (#6) to convert general-purpose electricity to
direct current for the other components. The most critical component is the
motherboard (#2), a plastic board on which several essential components are
mounted. This includes the central processing unit, or CPU, (#3), the main
memory (#4), and expansions slots (#5) for other hardware components. The
internal hard disk drive (#8) serves as the mass storage device for data files
and software applications. An optical disk drive (#7) makes it possible to read
from and write to CDs and DVDs. Other hardware components typically found
inside the computer case (but not shown in the figure) are a sound card, a
video card, and a cooling mechanism, such as a fan.
What are the
components that really make an information system work? In this lesson, we'll
explore IPOS (input, process, output and storage) and how this system works.
IPOS
Printing a photo is an example of short-term
output.
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Input is anything we wish to embed in
a system for some type of use. A variety of sources are used to input:
keyboard, scanner, microphone, mouse, even another computer. What we input has
a purpose - but until it is processed and generated in some form of output, it
doesn't do us much good.
Processing takes place in the internal parts of the
computer. It is the act of taking inputted data and converting it to
something usable. What we typically see on the screen in today's computer
world (known as what you see is what you get or WYSIWYG)
is the result of our input being processed by some program so we can have
usable output: an English paper, an edited photograph, this video you're
watching.
Output, or processed information in a usable format,
comes in many different forms: monitor or printer for visual work, a speaker
for audio. Sometimes our output is short-term, such as printing a photo, and
sometimes what we work on needs to be kept around for a while. That's where
storage comes in.
Storage is the term used to indicate we will
be saving data for a period of time. We store for many reasons: for
future reference; to prevent full loss of data; because we forget to purge.
But, storage is vital. There are several mediums on which we can keep output
and processed data: a hard disk, a USB drive, a CD.
Here are two anecdotes
to drive that point home. Someone lost an entire season of her son playing
hockey because she didn't back-up the video and photo files. And a fellow
student was working on a year-long bachelor's thesis and did not back it up the
first, the second or the third time she lost it - all at different stages of
completion, with a thesis over 60 pages long when she was done.
Quick - what does IPOS
stand for? That's right, input, process, output and store! Besides the four
functions of IPOS, an information system also requires feedback. This is how
future systems are revised and rebuilt - by receiving ideas, impressions and
constructive (or not so constructive) criticism by users and other
stakeholders.
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