Transcript Chapter 1

Chapter 1
Computers and Programming
Languages
1.1 Mechanical Devices
-Pascaline (invented in 1642 by Blaise Pascal)
-complicated set of gears
-worked similarly to a clock
-only performed addition
-never worked properly
-Stepped Reckoner (invented by Gottfried Wilhelm von Liebniz)
-suppose to add/subtract/multiply/divide
-included a cylindrical wheel
-tended to jam and malfunction
-Difference Engine (imagined in 1822 by Charles Babbage)
-was intended to print out numbers to the 40th place
-purpose was to produce navigation tables
-unfortunately never built
-Analytical Engine (designed around 1833 by Charles Babbage)
-supposed to follow a set of instructions stored on punch
cards
-during processing it was planned to store information in a
memory unit and make decisions based on the stored
content
-Although never built its design served as the template for
the modern computer
-Ada Byron (collaborator) considered first programmer
-Ada said it could never “originate anything” meaning that it
could not think
1.2 Electro Mechanical Devices
Tabulating Machine (invented by Herman Hollerith)
-invented to compute 1890 census
-used electricity instead gears to perform calculations
-holes representing information were punched in cards
-different locations of the holes represented different
info.
-cut the time to compute the census by over 2 years
Mark 1 (completed by team in 1944 led by Howard Aiken)
-team was from International Business Machines (IBM)
-used telephone relay switches to store information
-accepted data from punch cards
-since it could not make decisions about the data it was
nothing more than a sophisticated calculator
-51 feet in length, weighed more than 5 tons, and had
750,000 moving parts
1.3 First Generation Computers
Atanasoff-Berry Computer (ABC) – 1st electronic computer
-built between 1939-1942
-by John Atanasoff and Clifford Berry
-used binary number system of 0’s and 1’s (still used)
-contained hundreds of vacuum tubes
-stored numbers by electronically burning holes in paper
-patent application wasn’t handled properly and it took
nearly 50 years for Atanasoff to receive credit
ENIAC (Electronic Numerical Integration and Calculator)
-Built by John Mauchly & J. Presper Eckert
-finished in 1946 (took 3 years)
-originally a secret military project to calculate the
trajectory of artillery shells
-in its 1st demonstration it solved a problem that took a
team of mathematicians 3 days to solve in less than 20
seconds
-was the size of an average 3 bedroom house
1.4 The Stored Program Computer
-Alan Turing & John von Neuman both credited with idea
of stored programs
-EDVAC & EDSAC were 1st program controlled computers
-programs were written in machine language and
stored on paper tape
-UNIVAC (3rd computer to use programs)
-Used first computer language C-10 written by Francis
Holberton
-These computers were very large and expensive
1.5 Second Generation Computers
-William Shockley, John Bardeen, Walter Brittain of Bell
Laboratories invented the transistor in 1947
-Transistors were smaller, less expensive, and faster than
vacuum tubes
-Model 650 (released in early 1960’s by IBM)
-1st medium size computer
-very popular despite high costs
-Punch cards were replaced by magnetic tape giving
computers the ability to read and write data quickly and
reliably
1.6 High Level Prog. Languages
-Fortran (Developed in 1957 by John Backus and team)
-introduced commands READ and WRITE
-COBOL (Developed by Dept of Defense in 1959)
-ADA (Developed by Dept of Defense in 1970’s)
-supports real time applications
-still commonly used in the banking industry
-BASIC (Developed to teach students in the 1970’s)
-Object Oriented Prog. (OOP) languages were designed in the
1980’s (C++, Java, and Visual Basic are most common)
1.7 Third Generation Computers
-Integrated Circuits (IC’s or Chips)
-developed by Jack Kilby and Robert Noyce in the early
1960’s
-One chip could replace hundreds of transistors and
perform millions of calculations per second
-They have 2 settings on/off
-System 360 (released in 1964 by IBM)
-1st computers to use IC’s
-Inexpensive enough that universities and hospitals could
afford them
-so popular that IBM couldn’t keep up with demand
1.8 Mainframes
-Usually large and kept in their own room
-Used to store and process large amounts of data
-IBM System 360 was first mainframe
-Users used terminals to connect to mainframe
1.9 Fourth Generation Computers
-Microprocessor (invented by Marcian Hoff of Intel in 1970)
-Allowed the development of the microcomputer (desktop)
-Altair (1st desktop, built in 1975 by Apple Macintosh)
-Designed by Stephen Wozniak & Steven Jobs
-Used first G.U.I.
-IBM-PC (released in 1981 by IBM)
-immediate commercial success due to spreadsheet,
accounting, and word processing software
-The drop in cost now made the personal computer affordable
for the public
1.10 The Personal Computer
-Physical Components of computer are called hardware
-Monitor, keyboard, mouse, CD/DVD drive, case, etc.
-Input Devices (keyboard, mouse, CD/DVD drive)
-Output Devices (Monitors, printers are most common)
-Visual Aide (page 1)
-Motherboard (main circuit board)
-CPU/ALU
-Memory (ROM/RAM/SRAM)
-Bus/Data Bus/Address Bus/Control Bus
-Visual Aide (page 2)
-Software
-Operating System/Application
1.11 Networks
-Networks are widely used by businesses, universities, etc…
-Allows users to reliably share and exchange data
-Can reduce costs by sharing peripheral devices
-Can be set up to allow users access to only specific files
-Simplifies the backup process
-Allows users to communicate with email
-Classified by Size, Architecture, and Topology
-Size (LAN/WAN)
-Architecture (Client-Server/Peer-to-Peer)
-Topology (BUS/STAR/LOOP)
-Visual Aide (page 3)
1.12 Number Systems
-3 Common Number Systems (Binary, Decimal, Hexadecimal)
-Visual Aide (page 4)
-Decimal (base 10)
-uses numbers 0 – 9 (our common number system)
-example: 30
-Binary (base 2)
-uses numbers 0 & 1 (represents the on/off setting in IC’s)
-organized into 8-bit units called bytes
-example: 0001 1110
-Hexadecimal (base 16)
-uses numbers 0 – 9 and letters A – F
-example: 1E
-Unicode (set of 16 0,1’s to represent every letter/symbol)
-Visual Aide (page 6)
1.13 Storing Data in Memory
-Computer memory, file sizes, and storage device capacities are
measured in bytes. Large sizes might be in (KB/MB/GB/TB)
-Data stored in memory is referred to by an address
-each address has a unique binary representation
-storing the name JIM (see Visual Aide – page 5)
1.14 Social & Ethical Implications of
Computers
-Netiquette
-Do not attempt to access the account of another user
without authorization
-Do not share your password and change it periodically
-Use appropriate subject matter and language, and be
considerate of other people’s beliefs and opinions
-Laws to protect privacy
-Fair Credit Reporting Act of 1970
-Privacy Act of 1974
-Financial Privacy Act of 1978
-Electronic Communications Act of 1986
-Electronic Freedom of Information Act of 1996
-Safety and Freedom through Encryption Act of 1999
1.15 Protecting Computer
Software and Data
-Piracy (software, music, and movies)
-Precautions to avoid viruses
-Install antivirus software and update frequently
-Enable a firewall
-Monitor downloads from unknown sources (email/internet)
1.16 Ethical Responsibilities of the
Programmer
-Create programs that will “always” operate properly
-Test, debug, and collaborate to ensure this
-plan for errors for if and when they do happen
-Remember computers are being used more frequently in
areas where judgment is required, and computers can only
follow instructions so they must be comprehensive and
correct
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