Download presentation

Presentation is loading. Please wait.

Published byJesus Sparks Modified over 4 years ago

1
8 October 2013Birkbeck College, U. London1 Introduction to Computer Systems Lecturer: Steve Maybank Department of Computer Science and Information Systems sjmaybank@dcs.bbk.ac.uk Autumn 2013 Week 2a: History of Computing

2
8 October 2013Birkbeck College, U. London2 Computing Game Tom has a game in which he pretends to be a computer…

3
8 October 2013Birkbeck College, U. London3 Equipment A set of boxes Each box has a name: a, b, c, … Each box contains a piece of paper with a single number on it, e.g. box a contains 10 10 acbde f g 512-3111

4
8 October 2013Birkbeck College, U. London4 Instructions Tom carries out instructions such as: Add the number in box a to the number in box c, then put the result in box c, i.e. make the result the new number in box c. Subtract the number in box b from the number in box a. Put the result in box a. Multiply the number in box b with the number in box c. Put the result in box d.

5
8 October 2013Birkbeck College, U. London5 Observations The computer consists of a memory (the boxes), a device for changing the contents of the memory (Tom) and a list of instructions. The instructions are simple and there are only a few types (so far add, subtract and multiply). The instructions are carried out one at a time. There is no limit to the number of instructions which are carried out (Tom never gets tired).

6
8 October 2013Birkbeck College, U. London6 Hardware for Evaluating 1+2 Brain Abacus – rods and beads Mechanical – rods and gears Electromechanical – magnets open and close switches Vacuum tubes Transistors and integrated circuits

7
8 October 2013Birkbeck College, U. London7 Pascals Calculator: the Pascaline Image from http://www.tcf.ua.edu/AZ/ITHistoryOutline.htm Addition and subtraction only. For an illuminating moving example (in French – click on GO) see http://therese.eveilleau.pagesperso-orange.fr/pages/truc_mat/textes/pascaline.htm#haut

8
8 October 2013Birkbeck College, U. London8 Difference Engine Early computer for squaring numbers, and much more. Numerical results printed out in the form of tables. Designer: Charles Babbage (1791-1871) 1821: plans for a Difference Engine. 1832: partially built by Joseph Clement. 1834: plans for a more advanced computer, the programmable Analytical Engine. Never built. See http://en.wikipedia.org/wiki/Charles_Babbage

9
Calculation of Squares Using Differences xx*x1 st difference2 nd difference 00 111 2432 3952 41672 52592 8 October 2013Brookshear Section 0.29

10
8 October 2013Birkbeck College, U. London10 Difference Engine http://www.sciencemuseum.org.uk/images/I033/10303328.aspx Engine constructed from Babbages designs by the Science Museum

11
8 October 2013Birkbeck College, U. London11 Lego® Version of the Difference Engine Built by Andrew Carol http://acarol.woz.org/difference_engine.html

12
8 October 2013Birkbeck College, U. London12 Electromechanical Computer 1 st fully automatic computer. Vol16x2.4x0.6 m 3, weight 4500 Kg. Instructions read from punched paper. Store: 72 nums. of 23 dec. digits. Speed: + or - 0.3 s., * 6 s., / 15.3 s. http://en.wikipedia.org/wiki/Harvard_Mark_1 H. Aiken, 1944

13
8 October 2013Birkbeck College, U. London13 ENIAC 18,000 vacuum tubes Vol 30x2.4x0.9 m 3, Weight 27000 Kg Data input: card reader. Volatile store: twenty 10 digit decimal nos. Read only store: 100 nos. Programming: rewire Speed: + or – 0.2 ms, * 3 ms, / 25 ms. http://en.wikipedia.org/wiki/ENIAC J. Presper-Eckert and J. Mauchley

14
8 October 2013Birkbeck College, U. London14 Computing at Birkbeck 1945: Andrew Booth recruited by J.D. Bernal to work on mathematical methods for inferring crystal structure from X-rays. 1946-: builds series of computers, Automatic Relay Computer (ARC), ARC2, SEC, … 1957: establishes Department of Numerical Automation at Birkbeck See http://www.dcs.bbk.ac.uk/50years/50yearsofcomputing.pdf http://www.dcs.bbk.ac.uk/50years/50yearsofcomputing.pdf

15
8 October 2013Birkbeck College, U. London15 Computing at Birkbeck MSc student Norman Kitz working on the SEC (Simple Electronic Computer) at Birkbeck (1949). http://www.dcs.bbk.ac.uk/ 50years/50yearsofcomputing.pdf

16
8 October 2013Birkbeck College, U. London16 Algorithms An algorithm is an ordered set of unambiguous executable steps that defines a terminating process. It is implicit that something (e.g. a machine) carries out the steps.

17
8 October 2013Birkbeck College, U. London17 Informal Algorithms Directions to go from one place to another. Cooking recipes. How to use a device (TV, microwave, etc.) How to assemble flat pack furniture A list of instructions for Tom

18
8 October 2013Birkbeck College, U. London18 Algorithms and Computers An algorithms is converted into a list of instructions (program) for a particular computer. The details of the instructions vary from one computer to another If an algorithm is programmable on one computer, then it is programmable on any computer.

19
8 October 2013Birkbeck College, U. London19 First Example of an Algorithm Input: integers 12, 5 Output: quotient q and remainder r on dividing 12 by 5 Algorithm 1. q = 0; r = 12; 2. Subtract 5 from r; Increase q by 1; 3. Subtract 5 from r; Increase q by 1; 4. Output q, r; 5. Halt;

20
8 October 2013Birkbeck College, U. London20 Second Example of an Algorithm Input: strictly positive integers m, n Output: quotient q and remainder r on dividing m by n Algorithm 1. q = 0; 2. r = m; 3. If r < n, Output q, r; Halt; 4. r = r-n; 5. q = q+1; 6. go to 3;

21
8 October 2013Birkbeck College, U. London21 Third Example of an Algorithm Input: strictly positive integers m, n Output: quotient q and remainder r on dividing m by n Algorithm 1. q = 0; 2. r = m; 3. While r >= n, 4. r = r-n; 5. q = q+1; 6. EndWhile 7. Output q, r; 8. Halt;

22
8 October 2013Birkbeck College, U. London22 Exercise Sketch an algorithm that takes as input a strictly positive integer n and outputs an integer k such that

Similar presentations

OK

01/04/2014 cis110 1 Chapter 2 The development of computers Learning outcomes Outline the history of computers Explain Von-Neumann Architecture Explain.

01/04/2014 cis110 1 Chapter 2 The development of computers Learning outcomes Outline the history of computers Explain Von-Neumann Architecture Explain.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To ensure the functioning of the site, we use **cookies**. We share information about your activities on the site with our partners and Google partners: social networks and companies engaged in advertising and web analytics. For more information, see the Privacy Policy and Google Privacy & Terms.
Your consent to our cookies if you continue to use this website.

Ads by Google

Ppt on chromosomes and genes mutation Ppt on instrument landing system receiver Ppt on credit policy pdf Ppt on limitation act ontario Ppt on programmable logic array buy Ppt on pre ignition catalytic converter Ppt on cross site scripting Ppt on paintings and photographs related to colonial period lighting Ppt on brand marketing resume Slide show view ppt on mac