Basics Of Computer

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This document includes a brief overview of basic computing
concepts. It is the first in a series of three self-instruction
Internet tutorials produced by the Bedford
Public Library.

You can scroll through the document or jump to any of the

topics listed below. You can also print the entire document

by printing this page.

What is a Computer?
Software and Hardware
Hardware Components
Hardware Accessories
Operating System Software
Software Applications
Reference

What is a Computer?

Computers are not very intelligent devices, but they handle
instructions flawlessly and fast. They must follow explicit
directions from both the user and computer programmer. Computers are
really nothing more than a very powerful calculator with some great
accessories. Applications like word processing and games are just a
very complex math problem.

Software and Hardware

If you use a player piano as an analogy, the piano can be thought
of as the hardware and the roll of music as the software.

The software a series of very simple computer instructions carefully
organized to complete complex tasks. These instructions are written
in programming languages (like BASIC, PASCAL, C...) to help simplify
the development of applications.

The hardware is what sits on your desk and executes the software
instructions. The player piano is useless unless the roll of music
has been written correctly.

Hardware Components

Input Devices -- "How to tell it what to do"

- A keyboard and mouse are the standard way to
interact with the computer. Other devices include joysticks and game
pads used primarly for games.

Output Devices -- "How it shows you what it is doing"

- The monitor (the screen) is how the computer sends
information back to you, whether it be surfing the web or writing a
memo. A printer is also an output device.

Storage Devices -- "How it saves data and programs"

- Hard disk drives are an internal, higher capacity
drive which also stores the operating system which runs when you
power on the computer.

- "Floppy" disk drives

allow you to save work on small disks and take the data
with you.

Memory -- "How the processor stores and uses immediate
data"

- When you use a program, the computer loads a portion
of the program from the hard drive to the much faster memory (RAM).
When you "save" your work or quit the program, the data gets written
back to the hard drive.

Microprocessors -- "The brain of the computer"

- PCs primarily use microprocessors (sometimes
called the chip) manufactured by Intel. The older Intel versions
include the 386, 486 and now the Pentium line.

- Macintoshes use PowerPC processors by Motorola.

- Megahertz (MHz) is the internal processor speed in which
computer instructions are performed. The MHz speed does not always
indicate the power of the microprocessor. Newer processors can
execute more instructions at the same or slower MHz. For example, an
Intel 486 @100MHz is less powerful than a Pentium @75 MHz (but
the MHz is "faster").

Hardware Accessories

Modems

- Modems allow you to communicate with other computers
using a phone line. Modem speeds are in bits per second (14.4, 28.8
and 56 thousand bits per second are standard).

CD-ROM Drives

- A CD-ROM drive is a high capacity storage device
which lets you read data from the disk, but not write data back. The
speed of the drive (how fast the CD platter spins) is measured in
multiples from the first generation drives. New drives are up to 24X
(or 24 times the first drives), but while the CD spins faster, it is
not really 24 times faster in actual output.

Printers

- There are different types of printers (laser, ink
jet, dot matrix) with differing quality of output. They are measured
in dpi (dots per inch) and ppm (pages per minute), the higher the
better.

Scanners

- Scanners "digitize" printed material (like photos
and graphics) and save it to a graphic file format (like .GIF or
.JPG) for display on the computer.

Operating System Software

Operating system software provides a "user interface" for users to
manage files, start programs, customize computer settings, and other
tasks. The operating system also provides the fundamental core
computer functionality for programmers.

Intel based PCs use Microsoft Windows version 3.1 (older) or Windows
95 as the operating system. Macintoshes use the Macintosh operating
system.

Software Applications

Application software uses the operating system software and
provides the real functionality of a computer. Applications include:

- Word Processing (MS Word, WordPerfect, Ami...)
- Spreadsheets (Lotus 123, MS Excel...)
- Database (DBase, Fox Pro, Oracle...)
- Presentation (MS PowerPoint, Persuasion...)
- Internet Browsers (Netscape Navigator, MS Internet Explorer)
- Games

Reference

Here are some additional resources for more information on
computer basics.

White, Ron. How Computers Work. Ziff-Davis
Press, 1993.

White, Ron. How Software Works. Ziff-Davis Press, 1993.