Understanding Computers
Objectives
 Explain how input devices are suited to certain
kinds of data
 Distinguish between RAM and ROM
 Identify an appropriate output devices for
different types of data
 Explain the binary system used by computers
 Describe how software is written and
translated
Objectives
 Summarize the tasks of operating systems
 Identity two leading operating systems and
explain why compatibility is an issue
 Compare and contrast different kinds of
computers used in organization
 Compare and contrast different kinds of
computers used by individuals
Key Terms
 Command
 Computer System
 Flash Drives
 Handwriting-Recognition Software
 Motherboard
 Read-Only Memory (ROM)
 Speech-Recognition Software
 ASCII
 Compiler
Key Terms
 Interpreter
 Programmer
 Source Code
 Desktop Computer
 Handheld Computer
 Mainframe
 Netbook
 Server
 Super Computer
 Tablet Computer
Introduction
Computers come in many different shapes and
sizes. Some are large enough to fill a room.
Others can be held in the palm of your hand.
Whatever their size and capabilities, all these
computer have something in common. They
use electronic parts and instructions to
perform specific tasks.
Exploring Computer Systems
Parts Make a Whole – It takes many different parts
working together for a computer to do its job. A
computer system includes several devices that perform
the four basic functions of computing input, processing,
output, and storage.
Input Devices – Input means entering data, such as text,
images, or sounds. Computer user can choose from
several different input devices designed to work with
different forms of data.
Input Device (continued)
Graphics Card (Major Part)
Graphics cards, video cards or video adapters and
they're responsible for putting the image generated
by the computer onto a monitor. The display can
be in a number of resolutions such as 800 x 600,
1024 x 768 or 1280 x 1024. The greater the
resolution and the more colors the card displays.
Input Device (continued)
Sound Card (Major Part)
Microphones can be used to input sounds. As
with images, sounds stored on a storage device
or on the Internet can also be brought into the
computer as input.
Processing Devices
Motherboard (Major Part)
The name says it all - the Mother is the Heart of
the PC. This is the large printed circuit board
you'll see in the case which houses the main\
components of the computer. It has slots for
plugging-in memory and, probably I/O
controllers and connections for serial,
parallel and USB ports, floppy and hard disks
and PCI slots for plugging in cards such as a
video card, a modem, and a sound card.
Processing Devices(continued)
Processor (Major Part)
The processor or CPU (Central Processing Unit)
controls the computer. The processor is known as
the brains. This does the computer business. CPUs
have names, too, such as the Pentium II, III, IV,
AMD and Xeon. It executes instructions and
transports data around the computer system.
Processing Devices(continued)
The CPU temporary stores the instructions
and data it is using on chips called Random Access
Memory, or RAM. Once the computer is turned off,
RAM no longer stores any data.
A second kind of memory is called Read Only
Memory or ROM. These chips contain the
instruction that start the computer when you turn it
on. The instructions in ROM typically do not
change once this memory is placed on the
Motherboard.
Output Devices
A computer needs output devices to
display the results of its processing.
Different types of data are sent to different
devices. Text and images are displayed on
a computer screen. They can also be
printed by a printer. Sound data is sent to
speakers inside, or connected to, the
computer. You can also connect
headphones to a computer to listen to
sounds.
Storage Devices
Because memory is temporary, a computer needs a
secondary location for storing data permanently.
Devices such as hard disk drives, flash drives,
CDs/DVDs, and online storage are all popular
types of secondary storage.
Making Computers Work
How does a computer know what to do with
data in digital form? Software gives it the
instructions it needs. Experts called
Programmers write the instructions that
become software. Programmers write these
instructions, called source code, using a
Programming Language, example Postscript,
XML, HTML, XHTML and JAVA.
System Compatibility
The two most Popular Operating Systems are
Microsoft Windows and the Macintosh OS.
For many years, the two systems were not
compatible. That is, programs written for
one OS did not run on the other. Today,
some programs are written for both systems.
Most files can be written, saved, and read in
formats usable in both systems. Also, Utility
Programs can translate files that previously
may have been unreadable.
Compliers and Interpreters
Special programs called Compliers translate
the source code into binary form, using only
0s and 1s. The result, called Object Code, can
be read and acted on by a computer.
Sometimes, programs called Interpreters are
used to Translate the Source Code directly into
actions, bypassing the need for a complier.
Group and Individual Computing
Computer range in size from huge machines as
big as a room to devices so small they can fit in
your pocket. Each type of computer is suited to
handling a particular set of jobs in particular
settings.
Computer for Organizations – Companies and
other organizations use the full range of
Computers. Large Organizations can afford the
largest and most expensive machines, and such
companies are more likely to need all the
Processing Power that these huge machines have.
Computers for Organizations
Supercomputers – The largest and most
powerful computers can process huge
amounts of data very quickly. They are also
the most expensive computers.
Mainframes – The mainframe is another type
of computer used by government agencies
and large corporations. Mainframes are
designed so that many people can use the
same secure data at once. Examples: U.S
Armed Forces, Universities, Banks and
Insurance companies.
Computers for Organizations
Servers – Many organizations connect their
computers together in a network. All the
computers that are part of the network are
connected to a computer called a server. The
server holds data and programs that people
on the network can use on their personal
computers. An example of a server is what
we have at Patterson M.S. The software
applications on the individual computers
comes from the server in Mr. Waters office.
Computers for Individuals
Most individuals do not need as much
computing power as organization do. They
typically choose from among four types of
computers:
Workstations – The most powerful and
expensive personal computer are workstations.
Architects, engineers, designers, and others who
work with complex data use these machines for
their power and speed.
Computers for Individuals
Desktop Computers – Most individuals use
personal computers, or desktop computers, to
do everyday jobs more quickly and easily.
They are also used to connect to computer
networks such as the Internet.
Portable Computers – Some computers are
powerful enough to do the work of desktop
computers but can be easily moved. Laptop
and Notebook computers fit in a briefcase or
backpack. Smaller still are Netbook
computer, also called Subnotebooks or Mini
Laptops.
Computers for Individuals
A Mini Netbook is only 10” across, but does not
have a CD-ROM drive. Tablet Computers, such as
Apple’s iPad and Android Tablets, are also portable.
Handheld Computers – Computers small enough to
fit in your pocket are called handheld computers,
personal data assistants (PDA), or, with phone
service, a smart phone. Handhelds provide basic
organizational features such as address / phone
books, to do lists, and calendar functions, but can
also be used with a wide variety of “apps” to run
programs, play games, and interface with a PC.
Basic Steps to Start a Computer
 Input – enter external instructions via input
devices or instructions entered from within the
computer, such as from the CPU or Math CoProcessor (example: Power Button and Keyboard)
 Processing – once the instructions are entered they
are then processed throughout the computer’s CPU
(Pentium Processor) via operating system software
or application software.
 Output – after the information is processed it then
can be retrieved for further use, ex: sent to monitor
for viewing or sent to the printer for hard copy.