computer science
The Computer Era Begins: The First Generation
1950s: First Generation for hardware and software Vacuum tubes worked as memory for the machine Data written to magnetic drums and magnetic tapes Paper tape and data cards handled input The line printer made its appearance Software separates from hardware and evolves Instructions written in binary or machine code Assembly language: first layer of abstraction Programmers split into system and application engineers
An Apple a Day
1976: Steve Jobs and Steve Wozniak offer Apple I 1977: Apple II developed and released Based on Motorola 6502 processor Gains respect in industry, as well as among hobbyists Promotes application development VisiCalc spreadsheet program Drives Apple II sales Earns new title: killer app Draws attention of wider business community
Time-Sharing
Allocates system resources to multiple users Input with long paper rolls instead of punch cards Productivity gains offset by increased response time General-purpose machines broaden appeal Programmers gear software toward end user Distinctions between application level and OS level Statistical and accounting programs hide implementation details
The Internet
ARPA origins of new communication system Resource sharing Common protocols Fault tolerance 1969: ARPANET born Consisted of four computers at four locations Systems linked with Interface Message Processor ARPANET grows rapidly Protocols allow easy entry into network Electronic mail constitutes two-thirds of network traffic
The Personal Computer Revolution
Causes: Hardware vision of engineers Software developers seeking challenges Electronic hobbyists realizing a dream All necessary hardware and software elements were at hand or being developed Social, economic, and personal forces came together for support
Progression of Computer Electronics
Charles Sanders Peirce extends work of Boole Electric switches emulate true/false conditions of Boolean algebra Benjamin Burack implements concepts in 1936 logic machine John Atanasoff and Clifford Berry build a computer using vacuum tubes World War II Developmental turning point
One Last Thought
Development as a product of needs and wants Mixture of forces driving innovation Commercial and physical requirements (IC) Need to solve a problem (Analytical Engine) Desire to create something new (Apple I) Goal of winning a war (World War II) Need to succeed (Bill Gates) Evolutionary view Purpose of historical study Avoid mistakes and emulate triumphs
The Altair 8800
Development spurred by Popular Electronics Ed Roberts reports on the Altair 8800 Kit based on Intel 8080 Generates 4000 orders within three months Altair 8800 features I/O similar to ENIAC's Open architecture provides adaptability Portable
ENIAC and EDVAC (cont'd.)
EDVAC (Electronic Discrete Variable Automatic Computer) created in 1944 Recognized as the Von Neumann machine Superior model for descendant computers Operation governed by program in memory Programs could be modified Stored program concept made programs reusable British response: Colossus Helps crack German U-boat Enigma code All machines destroyed by 1960s
ENIAC and EDVAC
ENIAC's overhead Loud and large: 30 tons 18,000 vacuum tubes needed constant attention 6000 switches needed for arithmetic operations ENIAC's strengths Performs arithmetic and logic operations Made multipurpose with symbolic variables ENIAC'S weaknesses Could not modify program contents Had to be programmed externally
Living in the '70s with the Fourth Generation
Era of miniaturization LSI chips contain up to 15,000 circuits VLSI chips contain 100,000 to 1 million circuits Minicomputer industry grows UNIX operating system was created Free to educational institutions Microcomputer makes appearance
Enter Bill Gates, Paul Allen, and Microsoft
Gates and Allen Develop a BASIC interpreter High-level language for microcomputer programmers Briefly associate with MITS Formed Micro-Soft company in 1975 By 1981, Microsoft was on its way to becoming a multibillion-dollar company
IBM Offers the PC
IBM builds a microcomputer Adopts the Intel 8088 off the shelf Uses a nonproprietary CPU Creates approachable documentation Offers open architecture New product name: personal computer (PC) PC sold through retail outlets
MS-DOS
IBM chooses Microsoft to develop OS Microsoft introduces MS-DOS Based on Kildall's 8-bit CP/M Runs on 16-bit CPU (Intel 8088) Prevails over competition IBM calls operating system PC-DOS
IBM (Big Blue)
IBM dominates mainframe market by the 1960s Strong sales culture Controlled 70% of the market IBM vision Sharp focus on a few products Leverage existing business relationships Introduce scalable (and hence flexible) systems Lease systems with 10- to 15-year life spans
Circuit Boards in the Third Generation
Integrated circuits (IC) on chips Miniaturized circuit components on board Semiconductor properties Reduce cost and size Improve reliability and speed Operating systems (OS) Program to manage jobs Utilize system resources Allow multiple users
Intel
Intel 4004 chip 4004 transistors onboard Accrues greater functionality Precursor to central processing unit (CPU) Gary Kildall Writes OS for Intel microprocessor Software and hardware become separate commodities
Charles Babbage
Invents Difference Engine in 1823 Adds, subtracts, multiplies, and divides Designs Analytical Engine Components of modern computer Input and output devices Memory and CPU Not built due to lack of funds Collaborates with Ada Lovelace Byron Attribution of program loop concept Ada programming language namesake
Herman Hollerith
Invents electromechanical counter in 1880s Serves tabulation role in 1890 U.S. census Machine uses punch cards as input Single-purpose machine Company created around technology becomes IBM IBM rolls out multipurpose Mark I in 1944 Mark I rapidly made obsolete by vacuum tubes
Joseph Jacquard
Invents programmable loom in 1801 Jacquard loom weaved patterns in fabric Allowed input and storage of parameters Selection pins oriented with punch cards Similarities with player piano Concept of the stored program
The Microcomputer Begins to Evolve
Microcomputer's profitability lures more players Enter Radio Shack, IMSAI, Sphere, and others Altair's bus becomes S100 industry standard MITS stumbles Links prices of faulty hardware to BASIC Develops new model incompatible with 8080 1977 MITS sold off Hardware companies introduce competing models
Other PCs (and One Serious OS Competitor) Begin to Emerge
Microsoft two-fold argument to IBM Adapt open architecture concept to OS Allow Microsoft freedom to license its OS Microsoft answers Apple Windows 3.1 incorporates Mac's GUI features Competing PC clones appear with Microsoft's OS Microsoft leverages position OS presence drives application software sales Sales synergies and licensing give 90% of PC pie
Wartime Research Drives Technological Innovation
Military need for trajectory tables Weapons testing U.S. Navy Board of Ordnance helps fund Mark I U.S. Army funds ENIAC (Electronic Numerical Integrator and Computer) ENIAC runs 1000 times faster than Mark I Both were too late for the war effort
Super Software and the Web
Object-oriented programming (OOP) Computer-aided software engineering (CASE) Origin of the World Wide Web (WWW) 1990: Tim Berners-Lee develops hypertext Microsoft and Internet Explorer Web components Web pages Browser Network technology
Pascal and Leibniz Start the Wheel Rolling
Paper, wood, stone, papyrus tables, and abacuses as "computers 1622: invention of slide rule 1642: invention of mechanical calculator by Pascal 1694: Leibniz Wheel expands arithmetic operations
The Latest Generation (Fifth)
Parallel computing Aka parallel architecture CPUs joined for simultaneous task execution Three approaches SIMD (single instruction, multiple data) stream MIMD (multiple instruction, multiple data) stream Internetworking Uses Control Web pages, databases, and networks Mathematical modeling and scientific research
What About the Future?
Parallel computing Massive amplification of computing power Can be hosted by local networks as well as the Internet Wireless networking Bluetooth Embedded or ubiquitous computing Digitization of economy Privacy and security Open-source movement
Summary 2
Past leading to computer development included: Mechanical calculators invented in the 17th century by Pascal and Leibniz Jacquard loom of 1801 introduced the punch card and the concept of a stored program Charles Babbage designed a prototype of the modern computer: the Analytical Engine Herman Hollerith incorporated punch cards in his mechanical tabulating machines
Transistors in the Second Generation
Software innovations Assembly language limitations Appearance of high-level languages: FORTRAN, COBOL, LISP Hardware development Transistor replaces vacuum tube RAM becomes available with magnetic cores Magnetic disks support secondary storage
The Apple Macintosh Raises the Bar
Steve Jobs visits Xerox PARC Alto: graphics, menus, icons, windows, and mouse Observes functioning Ethernet network Learns about hypertext Jobs succeeds with Xerox ideas Picks up where Xerox (focused on copiers) leaves off Incorporates Palo Alto components in Macintosh 1984: Macintosh unveiled Graphical user interface (GUI) Mouse: point-and-click and ease-of-use
The Microsoft Era and More
The "browser wars" Microsoft integrates IE browser into Windows Netscape opposes Microsoft: goes open source The wars continue in court U.S. government files antitrust suit against Microsoft By 2001, most of antitrust suit was dropped or lessened Linux OS threatens Windows: Low cost, open source, and reliability
LANs and WANs and other ANs
The Internet as a network of networks Wide area network (WAN) Local area network (LAN) Wireless local area network (WLAN) Metropolitan area network (MAN) Urban area network (UAN) Network technologies Ethernet dominates Wireless technologies
The evolution of computers
Tied to mathematical evolution and driven by the need to master time and space From stone tablets to electronic machines Computer's chief purpose: manipulate mathematical and linguistic symbols Civilizations from the times of the ancients to the present Contributed to the development of computers and their science
UNIVAC (cont'd.)
UNIVAC First commercially viable computer U.S. Census Bureau is the first customer Faces skepticism from Howard Aiken (Mark I builder) UNIVAC and the 1952 presidential election Successfully predicts outcome during CBS broadcast Quickly adopted by all major news network
Summary 3
World War II drove computer innovation in the mid-20th century: ENIAC, Mark I, Colossus EDVAC's Von Neumann architecture Basic model for all later development Progress from vacuum tubes to integrated circuits Exponentially increased computer speed and simultaneously reduced the size and cost Microcomputer and Internet Latter 20th-century development Made computers ubiquitous
