Introduction to Computers
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What is a computer?
• A computer is a electromechanical device which can be
programmed to change (process) information from one
form to another.
– Do exactly as they are told.
– Digital devices: Understand only two different states (OFF
and ON)
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First Generation – Vacuum Tubes
• 1930’s – Vacuum tubes were used as electronic
circuits or electronic switches.
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First Generation – Vacuum Tubes
• First electronic digital computer built by Konrad Zuse, who developed his first
machine, the Z1, in his parents' living room in Berlin in 1938.
• Another early digital computer was built by Dr. John Atanasoff and his
assistant Clifford Berry, known as the ABC (Atanasoff Berry Computer) built
at Iowa State University during 1937-42.
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1946 - ENIAC
• First large-scale electronic digital computer was ENIAC (Electronic Numerical
Integrator and Calculator)
• 30 feet long, 8 feet wide, and 8 feet high
• 3 additions every second, (incredibly slow by today’s standards).
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1946 - ENIAC
• Grace Hopper, one of the first
programmers on the ENIAC and the
developer of the programming
language COBOL, says, “It was the
first machine that assisted the power
of man’s brain instead of the strength
of his arm.”
• ENIAC was developed long before the
days of silicon chips or microchips,
even before the transistor was
invented.
• Like ABC, ENIAC was made up of
vacuum tubes, over 18,000 of them!
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1951- UNIVAC 1
• 1951 the first commercially available computer was developed, the UNIVAC I
(UNIVersal Automatic Computer) using vacuum tubes
• 3,000 additions every second.
• In 5 years we were going a thousand times faster.
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1951- UNIVAC 1
• Rear Admiral Grace Hopper, USN, with other programmers.
• Photo taken, August 13, 1957
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Second Generation – Transistors
• 1947 - Walter Brittain and Willaim Shockley
invented the transistor at Bell Laboratories
• Replaced the vacuum tube as an electronic
switch
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1954 - TRADIC
•
•
•
•
TRADIC (TRAnsistorized Airborne DIgital Computer)
800 transistors.
First computer system to completely use transistors
First computer to be successfully operated in an aircraft, an environment
which was hostile to previous computer systems.
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Second Generation - Transistors
Transistors were:
• Smaller
• Faster
• More reliable
• Less expensive
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Third Generation – Integrated Circuits
• 1959, Jack Kirby and Robert Noyce at Fairfield Semiconductor (who was later
to become the cofounder of Intel Corp.) developed the first integrated circuit
(silicon chip or microchip).
• An integrated circuit (IC) is a system of interrelated circuits packaged
together on a single sliver of silicon.
• It is a way of placing multiple (millions) transistor devices into as single,
smaller device, the “microchip.”
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1960 – IBM 360
• 1 addition every billionth of a second
(nanosecond), or a billion additions every
second
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Third Generation – Integrated Circuits
ICs, chips, were:
• Smaller
• Faster
• More reliable
• Less expensive
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Fourth Generation - Microprocessor
• A microprocessor is a Central Processing Unit
(CPU) on a single chip.
• 1971, Intel Corp. introduced the first
microprocessor chip.
• Intel 4004
• 108 kHz and contained (equivalent of) 2300
transistors
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IBM used it for calculators not computers
• Busicom desk-top printing calculator, the
world’s first commercial product to use a
microprocessor.
• Used the Intel 4004 CPU.
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1975 - Altair 8800
• Ed Roberts and the
first microcomputer or
personal computer
(for the consumer) the
Altair 8800
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MITS Altair 8800
• Microcomputer - a
computer which
has a
microprocessor.
• Used the Intel
8080
Microprocessor
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Microprocessors
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1972 - Xerox Alto
• Xerox Alto – first
microcomputer.
• Developed at Xerox
PARC (Palo Alto
Research Center)
• Not for consumer
market.
• 1981 – Xerox Star
• Xerox executives
“just didn’t get it”.
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1976 - Apple I
• Steve Jobs and Steve Wozniak developed the
Apple I microcomputer in their basement.
• Though it was a flop, its successor became the
first popular home computer
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1977 – Apple II
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Others from 1977 - 1981
Kaypro
Commodore PET
2001
Osbourne
Tandy TRS-80
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Others from 1977 - 1981
Texas Instruments
Atari
IMSAI
Timex Sinclair
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1981 – IBM PC
• What everyone was waiting for, or fearing…
• “Open Architecture” and IBM
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1984 – Apple Macintosh
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1985 – Microsoft Windows 1.0
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1987 – IBM PS2 and OS2
• Closed architecture (similar to Apple)
• Never made it.
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Trends from 1990 to today…
• Microsoft continues to develop and
improve Windows with latest version
Windows XP and working on “Longhorn”
• LINUX operating system, an open source
version of UNIX, is taking on MS Windows
and gaining in popularity
• IBM has rebounded and continues to
make personal computers, laptops,
mainframes and minicomputers
• Apple continues to be a major player in
personal computers, especially for the
“creative market”, iPods, etc.
• Apple switching from IBM PowerPC CPU to
Intel
• DELL, Compaq, Gateway, HP, IBM
• Internet, networking, convergence
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Trends from 1990 to today…
•
•
•
•
Faster
Smaller
More reliable
Less
expensive
• Easier to use
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Traditional Types of Computers
• General purpose computers
–Mainframe
–Minicomputer
–Microcomputer (Personal Computer)
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Traditional Types of Computers
•
•
•
•
•
•
Mainframe
Computers
First computers, introduced in 1950s
Used by large businesses
Typically supported 100 to 500 users
Very expensive
Used for very large processing tasks
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Traditional Types of Computers
•
Minicomputers
• Typically supported 10 to 100 users
• Smaller and less expensive than mainframes
• The real difference is relative in terms of price, power,
marketing.
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Traditional Types of Computers
•
Microcomputers
(Personal Computer
or PC)
• Small, self-contained computers
with their own CPUs
• Used by home and business users
• Uses a microprocessor, a CPU
(Central Processing Unit) on a single
chip.
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Portable Computer
•
•
•
•
What are these types of portable
computers (a type of personal
computer)?
Desktop computers
Laptop computers
Personal Digital Assistants (PDAs)
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Networked computer
• Networked computer = Computers connected to other computers or
peripheral devices (printers, etc.) to share information.
• What is the difference between these two networked devices?
Dumb terminal
• No CPU (uses server’s)
• No Operating system (uses
server’s)
• Input and Output only
Intelligent terminal (computer)
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Embedded Computers
• Embedded computers – Computers found in
consumer goods in order to enhance their
function.
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Special Purpose Computers
• Special purpose or dedicated computers – A
device with a specific purpose such as game
system or information kiosk.
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Hardware versus Software
• Hardware = The
physical components
that make up a
computer system.
– More in a moment…
• Much more on all of
these items in later
presentations!
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Hardware versus Software
• Software = The
programs (instructions)
that tell the computer
what to do.
– System Software
– Application Software
– Stored on a storage
media such as hard disk,
CD-ROM, floppy disk,
tape, etc.
– More later…
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Hardware Components
• This is just an overview, more later…
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Computers, throw away technology?
• When first developed digital computers were
as large as a room and cost more than most
large business could afford.

Today systems costs have dropped to the level
where they are considered throw-away
technology
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Computers, throw away technology?
• Computer users fall roughly into two categories:



Home Use
Business Use
Home users want a system that can plug in and use
 Internet (Wireless)
Most
home
users
do
not
know
 E-Mail
how to set up a computer
 Games
 Learning (tutorials) system, and do not want to
bother upgrading a system
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Computers, throw away technology?
• Business today rely on computers for at least
some of their daily functions
• They view computers as a tool that helps their
employees become more productive
• The cost of the computer is minor compared to
the value it offers a company
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System Safety
Danger do not open there are no
user serviceable parts inside. Refer
to qualified service technician.
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System Safety
• No exposed lethal voltage inside a PC
• Power Supply is completely enclosed in a sealed unit
Some cases are stamped out of sheet metal and have
sharp edges
•
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System Safety
• Static Electricity can cause serious damage to PCs
• Facts about static electricity
- It takes approximately 3000 volts before a person
can feel the effects
- Walking across a carpet can generate as much as
35,000 volts
- Walking on vinyl tile can generate 14,500 volts
- It takes approximately 30-50 volts to damage
components
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System Safety
• Another major concern with computers is the
heat generated inside the case
• Never place a computer against a wall with no
air circulation
• Remove dust from the inside of a system
periodically
• Route wires out of the way so airflow is not
restricted inside
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http://www.computerhistory.org
Timeline of Computer History
http://www.computerhistory.or
g/timeline/?category=cmptr
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