Computer Basics
Computer Technology
What is a Computer
 Information
Processor
 Input
 Output
 Processing
 Storage
 Are
physical parts like monitor, mouse,
keyboard essential?
Computer History

Abacus

3,000 B.C.
Computer History

Jacquard Loom1801
 First “program”



Stored on metal
cards
Used in
manufacturing
Still used today
Computer History

Charles Babbage
1792- 1871
 Analytical Engine1833



Could store numbers/
do math
Programmed by metal
punch cards (software
)
Powered by steam,
had gears and levers
Computer History
 What
was the biggest advance that led to
modern computers?

Electricity
• Transistors
• Microchips
• Data storage
Computer History

Vacuum Tubes- 1941-1956


First generation electronic
computers
Vacuum Tubes are glass tubes
with circuits inside
Computer History
 UNIVAC/




ENIAC
Programmed by rewiring
Weighed 30 tons
Contained 18,000
vacuum tubes
Cost $487, 000
Computer History

Grace Hopper
 Recipient of
Computer Science’s
first “Man of the Year
Award”
 Programmed UNIVAC
Computer History

First Computer Bug
• Grace Hopper found a
moth stuck in a relay
responsible for a
malfunction
• Called it “debugging” a
computer
• What are today’s
computer “bugs”?
Computer History
 Transistors
replaced vacuum tubes-
1950’s

Made computers smaller and more reliable
Computer History
•Third Generation Computers used
Integrated Circuits (chips).
•Integrated Circuits are transistors, resistors,
and capacitors integrated together into a
single “chip”
•Circuits are transistors, resistors, and
capacitors integrated together into a single
“chip”
Computer History

1950’s Transistors replaced vacuum tubes in
computers.


Made computers smaller and more reliable.
1940’s – 1950’s- Computer Programming

Moved from rewiring to change function of a computer
to applications used to solve problems.
1970’s- IBM and other manufactures had
computers in most companies and universities
 1980’s- Computer changed from large tool only
for experts to a product for the general
consumer.

The Personal Computer

Apple Corporation founded in mid 1970’s.


Bill Gates of Microsoft- developed DOS (Disk
Operating System).



Steve Jobs and Steve Wozniak
1981- Became Operating System for IBM PC’s.
Became the “standard” operating system.
Students who graduated from high school or
college before 1985 seldom had access to
personal computers.
 End of 1980’s- many schools had computer labs
Personal Computer Hardware
 Hardware


Physical components
Power Supply- distributes electricity. Has a
fan to cool internal components.
CPU- Central Processing Unit- “brains” of the
computer. Tells all parts of computer what to
do. Performs calculating and logic functions.
Motherboard- Largest circuit- contains
expansion slots for additional circuits
(graphics card, etc.)
Peripherals
 Device
connected to the computer through
the BUS.
 Monitor, keyboard, printer, mouse.
 Video cards, modems, and sound cards
are inside the computer.
 Peripherals are generally Input or Output
devices.
Peripherals
Most PC’s use a Cathode Ray
Tube (CRT) similar to the tube in a TV.
 Monitor
Laptops and flat screens use a Liquid Crystal
Display (LCD) in their monitors.
 Hard

Drive/ CD- ROM Drive/ Disk Drive
Both Input and Output
 Printers-
we use a laser printer
Bits and Bytes
 Computers
operate through on/off
switches called bits.
 Bits are grouped into bytes.


Ex: A on keyboard = 01000001.
Byte is most common unit of measurement.
Software
 Instructions
that allow a computer to run
and act on the data given as input.
Software = Programs
 Two Types


Operating System
Application
Operating System/ Processing
Software

Most important software program.




Allows a computer to start up.
Controls how the CPU operates and communicates.
Makes computers user friendly.
We use Windows Vista
• Graphical User Interface- allows us to use mouse and icons
to use computer. We don’t need to know commands or
programming language.
• Older operating systems- DOS- had to type in commands for
EVERYTHING.
Application/ Program Software
 Includes
programs that allow you to make
the computer do what you want.


Ex: Word- write a letter, Dreamweaver- build a
web page.
Applications that run on one operating system
will not run on a different operating system.
• Ex: Windows can’t run on Unix of MacOS.
Personal Computer Memory

RAM- Random Access Memory- used for active
processing.



Ex: When you start Excel, the computer places the
program in RAM. When you open a document, it is
also placed in RAM.
When you save, the CPU copies the document from
RAM to permanent storage (ROM). When you save
and close memory is freed up.
RAM holds information only when there is electricity.
When machine is turned off/ loses power, whatever is
in RAM is also lost.
Personal Computer Memory
 ROM-
Read only memory
 ROM preserves its contents even when
the computer is shut down.
 ROM stores programs
 When you open a program it moves from
ROM to RAM.