Computer Terminology

Chapter 2 CIT 1100

History of Computers

• First known device used to compute was the Abacus 3000 BC

• 1617 John Napier created a crude slide rule referred to as Napier’s Bones

• First mechanical adding machine was created by Blaise Pascal 1642

• Difference Engine is considered the first general purpose computing machine created in 1822 by Charles Babbage

History of Computers

• Up until the 19th century all “computers” were mechanical

• In 1906 Lee De Forest invented the vacuum tube

• Scientists realized that they could now create an actual electronic computer

History of Computers

• Vacuum Tubes allowed early engineers to control the flow of electricity

• The methods needed to represent and store information took another 50 years to resolve

• During WWII there was a breakthrough

History of Computers• Its much easier to communicate with

a machine using Binary • A single Binary digit has only 2 states

– Its either ON– Or Its OFF

• The only drawback is you can only represent 2 things using Binary digits

• Decimal can represent 10 things

OFF ON

6

Bits

• Two patterns are known as the state of the bit.

• For example, magnetic encoding of information on tapes, floppy disks, and hard disks are done with positive or negative polarity.

The boxes illustrate a position where magnetism may be set and sensed; pluses (red) indicate magnetism of positive polarity (1 bit), interpreted as “present” and minuses (blue) (0 bit).

0 0 0 0 0 0 0 01 1 1 1 1 1 1 1

History of Computers

DECIMAL REPRESENTATION

BINARY REPRESENTATION

3987654210Allows you to count to ten using one character (0-9)

01Allows you to count to 2 using one character (0-1)

Binary

• The Binary Numbering system is used by computers to represent data

• People prefer to communicate using Decimal numbering

• To communicate with hardware you must break everything down to its most basic form BINARY

Decimal • We have become familiar with base 10

because that’s the way we have always counted.

• We have memorized ten characters that represent ten symbols used to represent numbers 0 1 2 3 4 5 6 7 8 9

Decimal Math

2+24

7+2

9

9+1

0

1 5+5

0

1 Carry

Binary Math

1 1+0

1+1

0

1 111111+ 1

0

1

0

1

0

1

0

1

0

1

0

1

Counting

0 00 0 01 1111 23456789101112131415

Binary Decimal

The CPU

Central Processing Unit– Input – Processing– Output– Storage

INPUT

Switch OFF 0Switch ON 1

Using one piece of wire with one light bulb we can represent 2 different states in Binary ON / OFF

ASCII CHARACTERS

• In order to create meaningful data on a computer you need the following symbols:

• Counting Numbers 0-9• Alpha Characters A-Z

• Alpha Characters a-z

• Punctuation !@#$%^&*() .,:;

• Special Characters

256 Characters

16

ASCII-7• In the early days, a 7 bit code

was used, with 128 combinations of 0’s and 1’s, enough for a typical keyboard.

• The standard was developed by ASCII (American Standard Code for Information Interchange)

• Each group of 7 bits was mapped to a single keyboard character.

0 = 0000000 1 = 0000001 2 = 0000010 3 = 0000011… 127 = 1111111

DATA BUS

• With one wire you can represent 2 states• With two wires you can represent 4 states• With three wires you can represent 8 states

2x = number of possible combinations of 1s & 0s

DATA BUS

• Using a single bit, with two discrete states, gives only two options (ON or OFF).

• 1 bit, 2 unique patterns: 0 or 1• 2 bits, 4 unique patterns: 00, 01, 10 or 11• 4 bits, 16 unique patterns: 0000, 0001, 0010, 0010, …1111• 8 bits, 256 unique patterns: 00000000, 00000001, 00000010, … 11111111

Binary

DATA BUS

• With 8 Wires you can represent 28 = 256 unique characters

INPUT DEVICEABabHK1234

High Order Bit

Low Order Bit

21

ByteByte = A collection of bits (usually 7 or 8 bits) which

represents a character, a number, or other information.• More common: 8 bits = 1 byte• Abbreviation: B

22

Bytes1 byte (B)

Kilobyte (KB) = 1,024 bytes (210) • “one thousand bytes” 1,024 = 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2

Megabyte (MB) = 1,048,576 bytes (220) • “one million bytes”

Gigabyte (GB) = 1,073,741,824 bytes (230) • “one billion bytes”

Definitions

• BIT – The smallest piece of data a computer can work with

• BYTE – 8 Bits • BUS – A piece of wire that carries a signal• Clock – Used to synchronize evens

Labs Hints

• Locate & identify the connector that delivers power to the motherboard. Is the connector an AT or ATX style?

http://www.youritronics.com/how-to-power-up-an-atx-power-supply/

http://www.playtool.com/pages/psuconnectors/connectors.html

Labs Hints

• Molex vs. berg connector?

4 Pin Berg Connector4 Pin Molex Connector

20 Pin Molex

Labs Hints

• Does your system support PCI –E slots?

Labs Hints

• Scan the motherboard for any terminal blocks and jumpers.

• These numbers are just FYI. Each venders have their own different numbers and purpose reference chart.

Labs Hints

• What Socket is supported by the system?

Labs Hints

• North Bridge chip type vs. South Bridge chip type

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Labs Hints

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