Chapter 1
History
of
Computers
Objectives & Goals
 Technology led up to the modern day computer.
 Define a Computer
 Women contribution in the development of
computers
 Role of government in the development of
computers
 Role of War World II in the development of
computers
Mechanical Devices
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Pascaline
Stepped Recknor
Thomas Arithmometer
Difference Engine
Analytical Engine
Pascaline
Set of gears (similar to a clock)
Addition only
Device did not work properly
Blaise Pascal
 French Philosopher & Mathematician
 Invented the Pascaline in 1642
Stepped Reckoner
Gottfried Wilhelm von Leibniz
 German Mathematician
 1671 introduced the Step Reckoner, a
device which, as well as performing
additions and subtractions, could multiply,
divide, and evaluate square roots by series
of stepped additions.
 Leibniz wheel – cylindrical wheel for the
Stepped Reckoner.
 Stepped Reckoner was very unreliable.
Thomas Arithmometer
Around 1820, Charles Xavier Thomas
created the first successful, mass-produced
mechanical calculator, the Thomas
Arithmometer
It could add, subtract, multiply, and divide.
It was mainly based on Leibniz' work.
Difference Machine
Charles Babbage
Charles Babbage
• Father of Computing
• 1822 a British mathematician and
inventor. Charles Babbage try to
create the Difference Engine.
• Difference Engine was never created.
• Ideals of the Difference Engine led up
to the Analytical Engine
Analytical Engine
 Created by Charles
Babbage in 1833
 Used punch cards for
set of instructions
 Was never built
 The design served as a
model for the modern
computer.
Punched Cards
 In the early 1800s, a French silk weaver
called Joseph-Marie Jacquard invented a
way of automatically controlling the warp
and weft threads on a silk loom by
recording patterns of holes in a string of
cards. In the years to come, variations on
Jacquard's punched cards would find a
variety of uses, including representing the
music to be played by automated pianos
and the storing of programs for computers
Ada Byron
 Augusta Ada Byron (Lovelace)
was born December 10, 1815
 A mathematician and scientist.
 Ada suggested to Babbage
writing a plan for how the engine
might calculate Bernoulli
numbers. This plan, is now
regarded as the first "computer
program." A software language
developed by the U.S. Department
of Defense was named "Ada" in
her honor in 1979.
Herman Hollerith
• Hollerith’s Tabulating Machine
• Created for a contest by the U.S Census
Bureau
• Invented by Herman Hollerith in 1890
• Used electricity instead of gears to perform
calculations
• Used punch cards to program
Hollerith’s Tabulating Machine
 Tabulating Machine Company (1896) was a
predecessor to the International Business
Machines Corporation (IBM).
Mark I
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•
•
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Created by IBM in 1944
Howard Aiken of Harvard assisted IBM
Used relay switches and punched cards
Mark I was not considered a computer
(calculator)
Mark I
 The Mark I was constructed out of
switches, relays, rotating shafts, and
clutches, and was described as sounding
like a "roomful of ladies knitting." The
machine contained more than 750,000
components, was 50 feet long, 8 feet tall,
and weighed approximately 5 tons!
Atanasoff-Berry Computer
(ABC)
• The first electronic computer built between
1939 –1942.
• Created by John Atanasoff and Clifford
Berry at Iowa State University
• Used the Binary System (1’s and 0’s)
• Used Vaccum Tubes and switches
• Did not get recognized until 50 years later
ENIAC
• Created by John Mauchly and J. Presper
Eckert in 1943
• ENIAC – Electronic Numerical Integration
and Calculator
• Built at the Univ. of Pennsylvania
First Generation
Computers
• ABC
• ENIAC
• EDVAC
• EDSAC
• UNIVAC
Computer
 Is an electronic machine that accepts
data, processes it according to
instructions, and provides the results as
new data. A computer can make simple
decisions and comparisons.
nd
2
th
4
–
Generation
Computers
Stored Program Computer
High-Level Programming Language
Mainframes
The Stored Program Computer
• Alan Turing and John von Neumann came
up with the idea of stored programs in a
publication.
• John presented his idea of the stored
program concept by storing a program on
the CPU that would control the computer
functions.
Alan Turing
 Developed the idea of a universal machine.
He envisioned a computer that could
perform many tasks by simply changing the
program instead of components.
John von Neumann
Created the CPU which stored
programs so you won’t have to
flip switches or pull wires to
change instructions
Programs
• Is a list of instructions written in a
special language that the computer
understands.
CPU
• Central Processing Unit
• Consisted of different elements used to
control all the functions of the computer
electronically
Machine Language
• Consists of 0’s and 1’s which
represented on or off for switches.
EDVAC and EDSAC
• Created by Mauchly, Eckert, & von
Neumann
• EDVAC – Electronic Discrete Variable
Automatic Computer
• EDSAC – Electronic Delay Storage
Automatic Computer
• These computer were designed to solve
many different problems by simply
entering new instruction
• Theses computers used machine
language for instructions.
UNIVAC
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•
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UNIVersal Automatic Computer
Used stored programs
Built by Mauchley and Eckert
Sold to the U.S Census Bureau in
1951.
Second Generation
Computers
Transistor
• Invented by William Shockley, John
Bardeen, and Walter Brittain in 1947.
• The invention of the transistor made
computers smaller and less
expensive and increased calculating
speed to up to 10,000 calculations
per second.
Model 650
• The IBM 650 was one of IBM’s early
computers, and the world’s first massproduced computer. It was announced in
1953, and over 2000 systems were
produced between the first shipment in
1954 and its final manufacture in 1962.
Third Generation
Computers
Integrated Circuits
• Replaced the transistor
• Led to the 3rd generation of computers.
• Created by Jack Kilby and Robert
Noyce.
• Also known as a “chip”
• 1 - IC replaced hundreds of transistors
Integrated Circuits
• Silicon Wafers with intricate circuits
etched into their surfaces and then coated
with a metallic oxide that fills the etched
circuit pattern.
• IBM System 360 first to use integrated
circuit.
Mainframes
• IBM 360 1st mainframe
• Is a large computer system that is
usually used for multi-user
applications.
• Consists of a keyboard & monitor
• Connects to the computer by wires
in which the computer might be in
another room.
• Also known as dummy computers
Fourth Generation
Computer
Microprocessor
• Created in 1970 by Marcian Hoff an
engineer at Intel Corp.
• Entire CPU on one chip
Microcomputer
• Uses the microprocessor
• Altair the 1st microcomputer created in
1975
• Fits on a desktop
• Apple was created in 1976 by Stephen
Wozniak and Steven Jobs
• Very inexpensive
Stephen Wozniak & Steve Jobs
Computer Components
The Personal Computer
Memory: ROM and RAM
The CPU
Number System
Storing Data in Memory
Storage Devices
The Personal Computer
 Consists of:
– Monitor
– Base Unit
– Keyboard
– Diskette Drive
– CD-ROM Drive
– Mouse
Data Flows of Computer
Components
Input
Memory
CPU
Output
Software
 Is instructions stored as electronic data
that tells the computer what to do.
Operating System Software
o Runs automatically when the computer is
turned on and enables the user to
communicate with the computer.
• Application Software
o Application, Program, or software – is
written by programmers to perform a
specific task.
Two Types of Memory
ROM – Read Only Memory – contains
the most basic operating instructions for
the computer. Data on the ROM is
permanent
RAM – Random Access Memory –
temporary memory where data and
instructions can be stored. Data is lost
when the computer is turned off.
CPU
Central Processing Unit – directs the
processing of information throughout the
computer.
CPU contains the ALU (Arithmetic Logic
Unit) which performs arithmetic and logic
operations.
ALU is measured in nanoseconds
(billionths of a second)
Numbering System
Electrical circuits on an IC have one of
two states (off or on).
Binary System is used to represent the two
states (1 and 0)
Each 1 or 0 represents a “bit”
Bit- (BInary DigiT) is the small memory
unit.
Byte
Byte – equals 8 bits.
Byte - is a unit of digital
information in computing and
telecommunications that most
commonly consists of eight bits.
Nibble
• 4 bits or half a Byte
Word
Bits grouped in units of 8 to 64 or
more are called “words”.
Size of the word depends on the
computer system.
LONG WORD
Greater than 64 bits
Integers
Stored in to bytes.
Range –32,768 to 32,767
GO OVER BINARY, HEX
Numbers
Number Systems
Binary – Base 2
Octal – Base 8
Decimal – Base 10
Hexadecimal – Base 16
ASCII
 American Standard Code for Information
Interchange.
 Allows computers to interchange information.
 Each letter of the Alphabet both uppercase and
lowercase, digits, and symbols are represented
by a number.
ANSI
ANSI – American National Standards
Institute
First 127 characters of the ASCII set
The ANSI character does not vary from
computer to computer.
ASCII characters (128 to 256) – do vary
depending on computer.
Storing Data in Memory
 Size of memory is measured in bytes.
 Byte 20 = 1
 Kilobyte 210 = 1024
 Megabyte 220 = 1,048,576
 GigaByte 230 = 1,073,741,824
 Terabyte 240 = 1,099,511,627,776
 Petabyte 250 = 1,125,899,906,842,624
 ExaByte 260 = 1,152,921,504,606,846,976
 Zettabyte 270 = 1,180,591,620,717,411,303,424
 Yottabyte 280 = 1,208,925,819,614,629,174,706,176
• Nonabyte 290 = 1,024 YB = 1,048,576 ZB
• Doggabyte 2100 = 1,024 NB = 1,048,576 YB
Memory
Data stored in memory is referred to by
an address.
Address – is a unique binary
representation of a location in memory.
For data to be addressable in memory, it
must usually be one byte.
Real Numbers
Known as Floating Point Numbers
Numbers that contain decimal points.
Usually 4 to 8 bytes of memory
Mantissa (fractional part)
Overflow error can occur just like integers
Overflow Error
Occurs when the number of bits that are
needed to represent the integer is greater
than the size of two bytes.
Roundoff Error
Occurs when there are not enough bits to
hold the mantissa.
Storage Devices
Most computers today has three
drives
–Diskette Drive/USB
–CD-ROM Drive
–Hard-disk Drive
Storage
• Punch Cards
• Magnetic Tape
• High Speed reels
• Magnetic tape allowed user to read
(access) and write (store) data quickly
and reliably.
High-Level Programming
Language
• English-like instructions and are easier to use
than machine language.
– Fortran – FORmula TRANslator
– COBOL – COmmon Business Oriented
Language
– BASIC – Beginner’s All-Purpose Symbolic
Instruction Code
COBOL
• Most widely used program
• Designed Grace Murray Hopper
– Rear Admiral in the Navy
• Developed for the Department of Defense.
– DOD also developed Ada (Named after Ada
Byron)
BASIC
• Beginner’s All-Purpose Symbolic Instruction Code
• Developed in 1960 by John Kemeny and Thomas
Kurtz at Dartmouth.
• Evolved into Visual Basic which is wide used today
for window programming.
Grace Murray Hopper
Grace Brewster Murray Hopper was born in New York City on
December 9, 1906, to Walter Fletcher Murray and Mary Campbell
Horne Murray. At age seven, she showed a particular love for gadgets,
disassembling seven alarm clocks in the attempt to determine how they
worked. Hopper's parents provided a strong foundation for her
inquisitiveness. Hopper's first assignment was under Commander
Howard Aiken at the Bureau of Ordinance Computation at Harvard
University. There she became the third programmer of the Mark I, the
world's first large-scale automatically sequenced digital computer. The
computer was used to calculate aiming angles for Naval guns in varying
weather conditions. They spent countless hours transcribing and
inputting codes for Mark I and its successors, Mark II and III. Hopper
received the Naval Ordnance Development Award in 1946 for her work
on the Mark series.
During her work with Mark II, Hopper was credited with coining the
term "bug" in reference to a glitch in the machinery.