Transcript Course Introduction & Number Systems

ISP 121
Personal Computers
A Little History…
Personal Computers
When were the world’s first minicomputer and
first mass-produced minicomputer created?
A. 1945
C. 1965
B. 1957
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.
Personal Computers
What company was founded in
1976 and revolutionized
personal computing ?
Apple Computers
The Apple II
microcomputer,
introduced in 1977
and was a hit with
home users.
Apple II
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 MSDOX 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
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 thenstandard command line interface.
Microsoft first introduced Windows in
November 1985 as an add-on to MSDOS in response to the growing
trend of graphical user interfaces
(GUI) popularized by the Macintosh.
Early Video Games
The 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 pressuresensitive, 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