1 Chapter 1 The Big Picture

2 2 Computing systems are dynamic entities used to solve problems and interact with their environment. They consist of devices, programs, and data. Computing Systems

3 3 Hardware - The physical elements of a computing system (printer, circuit boards, wires, keyboard…). Software - The programs that provide the instructions for a computer to execute. Data - Information in a form a computer can use. Computing Systems

4 4 Communication Application Operating System Programming Hardware Information Layers of a Computing System

5 5 Abstraction - A mental model that removes complex details. This is a key concept. Abstraction will reappear throughout the course – be sure you understand it! Abstraction

6 6 AbacusAbacus (2400 BC) An early device to record numeric values. Blaise PascalBlaise Pascal ( ) Created a mechanical device to add and subtract. Gottfried Wilhelm von LeibnizGottfried Wilhelm von Leibniz ( ) Created a mechanical device to perform all four whole number operations. Joseph Jacquard Jacquard’s Loom (1801), the punched card Early History of Computing

7 Charles BabbageCharles Babbage ( ) Difference Engine, Analytical Engine Augusta Ada Byron (Lovelace) Babbage’s assistant Considered to be the first Programmer,  Invented the concept of the loop William BurroughsWilliam Burroughs ( ) Adding Machine Herman HollerithHerman Hollerith ( ) Electro-mechanical Tabulator

8 7 Alan TuringAlan Turing ( ) Turing Machine - an abstract mathematical model Artificial Intelligence Testing Early computers launch new era in mathematics, physics, engineering and economics. Harvard Mark IHarvard Mark I (1939) ENIACENIAC - Electronic Numerical Integrator and Calculator EDVACEDVAC - Electronic Discrete Variable Automatic Computer first machine with a stored program UNIVAC IUNIVAC I - Universal Automatic Computer (1951) Early History of Computing

9 8 Vacuum Tubes Large, not very reliable, generated a lot of heat Magnetic Drum Memory device that rotated under a read/write head Card Readers  Magnetic Tape Drives Sequential auxiliary storage devices First Generation Hardware ( )

10 9 Transistor Replaced vacuum tube fast, small, durable, cheap Magnetic Cores Replaced magnetic drums information available instantly Magnetic Disks Replaced magnetic tape data can be accessed directly Second Generation Hardware ( )

11 10 Integrated Circuits Replaced circuit boards smaller, cheaper, faster, more reliable Transistors Now used for memory construction Terminal An input/output device with a keyboard and screen Third Generation Hardware ( )

12 11 Large-scale Integration Great advances in chip technology PCs, the Commercial Market, Workstations Personal Computers were developed as new companies like Apple and Atari came into being. Workstations emerged. Fourth Generation Hardware (1971-?)

13 12 Parallel Computing Computers rely on interconnected central processing units that increase processing speed. Networking With the Ethernet protocol, small computers could be connected and share resources. File servers connected PCs in the late 1980s. ARPANETARPANET(1969) and LANs  InternetInternet Parallel Computing and Networking

14 13 Machine Language Computer programs were written in binary (1s and 0s). Assembly Languages and translators Programs were written in artificial programming languages and were then translated into machine language. Programmer Changes Programmers divide into application programmers and systems programmers. First Generation Software ( )

15 14 High Level Languages English-like statements make programming easier. Fortran, COBOL, Lisp are examples. High-Level Languages Assembly Language Machine Languag e Second Generation Software ( )

16 15 Third Generation Software ( ) Systems Software  utility programs,  language translators,  and the operating system, which decides which programs to run and when. Separation between Users and Hardware Computer programmers began to write programs to be used by people who did not know how to program.

17 16 Application Package Systems Software High-Level Languages Assembly Language Machine Language Third Generation Software ( )

18 17 Structured Programming Pascal, C, C++ New Application Software for Users spreadsheets word processors database management systems Fourth Generation Software ( )

19 18 Microsoft The Windows operating system, and other Microsoft application programs dominate the market. Object-Oriented Design Based on a hierarchy of data objects (i.e. Java). World Wide Web Allows easy global communication through the Internet. New Users Today’s user needs no computer knowledge. Fifth Generation Software (1990- present)

20 Programmer / User Applications Programmer (uses tools) User with No Computer Background Systems Programmer (builds tools) Domain-Specific Programs Computing as a Tool