ISP 121

Personal Computers

A Little History…

Personal Computers

When were the world’s first minicomputer and first mass-produced minicomputer created?

A. 1945

B. 1957

C. 1965

D. 1970

About the First Minicomputer

• Created by Digital Equipment Corp. (DEC) which was founded by Ken Olsen and Harlan Anderson

• It was named the PDP-8

• It cost $18,000

• It was marketed to businesses.

Apple Computers

The Apple II microcomputer, introduced in 1977 and was a hit with home users.

Apple II

What company was founded in 1976 and revolutionized personal computing ?

Personal Computers

About the Founders of Apple Computers

• Founded by Steve Jobs and Steve Wozniak.• Steve Jobs sold his Volkswagon minibus and Steve

Wozniak sold his scientific calculator for a total of $1,300 to raise money to start the business.

The Rival…

In 1980 IBM decided to market a low-cost single-user personal computer in response to Apple Computer's success in the burgeoning market.

On 12 August 1981, the first IBM PC went on sale. There were three operating systems (OS) available for it but the most popular and least expensive was DOS. IBM licensed DOS from Microsoft and named it PC-DOS (also known as MS-DOX for non-IBM platforms).

Operating Systems

It was the most widely used member of the DOS family of operating systems and was the dominant operating system for the PC compatible platform during the 1980s.

Interfaces

Microsoft first introduced Windows in November 1985 as an add-on to MS-DOS in response to the growing trend of graphical user interfaces (GUI) popularized by the Macintosh.

The Macintosh (MAC), from Apple Computers was named after the McIntosh apple. The original Macintosh was released on January 24, 1984. It was the first commercially successful personal computer to use a graphical user interface (GUI) and mouse instead of the then-standard command line interface.

Early Video GamesThe original Atari was founded in 1972 and it was a pioneer in arcade games, home video game consoles, and home computers.

The original PONG arcade unit was released by Atari on November 29, 1972. It was certainly the first video game to win widespread popularity, in both its arcade and home console versions.

The Atari 400 was designed primarily as a computer for children. It has an "advanced child-proof design featuring pressure-sensitive, wipe-clean keyboard“ and a single cartridge port under the front cover.

and Now…

How do Computers Store Numbers?

How do Humans Count?

• The Babylonians used a base-60 numbers system. How is it used today?

• The Hindu-Arabic numeral system is a base-10 system which we commonly represent by using 0,1, 2…9. Why does this system make sense?

How do Computers Count?

• Computers are logical electronic devices.• The data is just a combination of two states –

“on” or “off”.• These states are called binary digits or bits

and have either the value of 0 or 1.• This is considered a base-2 or binary number

system.

Binary Number System

• Maximum number of different values that can be represented by n bits is 2n.

• One byte = 8 bits

• Computers start counting at zero

• Binary numbers can be written with a subscript 2

• Uses a place system