An introduction to computer sciences and computer engineering through the computing history.

1. History of Computing http://www.vigneras.name/pierre Dr. Pierre Vignéras This work is licensed under a Creative Commons Attribution-Share Alike 2.0 France. See http://creativecommons.org/licenses/by-sa/2.0/fr/ for details

2. Text Books Books Reference Book: New Perspectives On Computer Concepts Parsons and Oja National Book Foundation The Web: http://wikipedia.org C- How to program (Third Edition) Introduction C++ and Java Deitel & Deitel Prentice Hall

4. No exit before the end of the class

6. Fixed timing (you may suffer if you arrive late)

7. Spread Out (do it quickly to save your time)

8. Papers that are not strictly in front of you will be considered as done

9. Cheaters will get '-1' mark

10. Your head should be in front of your paper! Class, Quiz & Exam Rules Rules

12. Mid: 30 %

13. Final: 50 %

14. A final average below 50/100 will be assigned a failed mark: F. Grading Policy

16. Bits & Bytes

18. Moore's Law

20. Turing Machine, Lambda Calculus & Boolean Algebra

21. Algorithms (pseudo-code, flowcharts)

23. Type System

24. Type checking (static vs dynamic, weak vs strong) Outline (Important points)

26. Eras (Unix, Apple, IBM PC, Mac, Windows)

28. Network Layers (OSI, TCP/IP)

29. Network Topology Outline (Important points)

30. Outline

32. Personal Computers, Laptop

33. PDA, Cellular Phones, Smart cards I. Basics

36. Used to represent (almost) everything

39. Numeral Bases I. Basics

41. Motherboard

42. Processor (CPU)

43. Memory (RAM)

44. Extension Cards

45. Power Supply

46. Optical disk drive (CD/DVD)

47. Hard Disk Drive (HDD)

48. Keyboard

49. Mouse I. Basics

53. the character 'F',

54. the instruction: “increase the value of the next cell by one”

55. The first and third “property” are TRUE, others are FALSE,

56. Anything else... I. Basics

60. Intel PIV ~ 2 IPC

63. Contains a Graphic processor (GPU)

64. Needs its own memory I. Basics

67. Hard Drives: [60 – 800 ] GB

70. Screens: CRT 17' & 19'; TFT 15' & 17' (trend) I. Basics

73. accessible via the Internet, as are many other services

74. www != Internet

76. fish://192.168.1.1/documents (SSH) I. Basics

79. When you enter a keyword, the search engine look in its table for a matching [word, {URLs}]

84. See: http://tools.ietf.org/html/rfc1855 - RFC1855 (standard) http://www.penmachine.com/techie/emailtrouble_2003-07.html (short) I. Basics

85. Outline

87. Languages

88. Complexity

89. Computability

91. http://www.eingang.org/Lecture/ II. History

93. Religion & ceremonies according to time

96. Abacus (China), Pascaline (Blaise Pascal, 1642), The Difference Engine (Charles Babbage, 1812) II. History/Hardware

98. For U.S. Census Bureau

99. Used until the highly controversial United States presidential election of 2000

101. Cards (http://en.wikipedia.org/wiki/Punch_card) II. History/Hardware

102. Cards (http://en.wikipedia.org/wiki/Punch_card) II. History/Hardware

104. Uses binary system II. History/Hardware

106. Four operations on 23 decimals numbers

107. Subroutines (logarithm & trigonometric functions)

108. 3 to 5 seconds per multiplication

110. “Wire your own“ instruction technique II. History/Hardware

112. Often used subroutines can be stored in memory

114. Von Neumann Architecture II. History/Hardware

116. collection of tiny transistors which are connected together

120. Moore's law II. History/Hardware

121. Moore's Law effect II. History/Hardware

123. New type of technology will replace current integrated-circuit technology, and that Moore's Law will hold true long after 2020. II. History/Hardware

124. General Moore's Law II. History/Hardware

128. II. History

133. And what about us? Is the proposition TRUE? Yes! II. History/Theory

136. how to move the head

138. Turing Machine (Abbrev: TM) (http://en.wikipedia.org/wiki/Turing_machine) II. History/Theory

140. The input form in which the parameters are presented on the tape

141. The output form in which answers will be represented on the tape when the Turing machine halts

142. The initial state of the Turing machine

143. The machine program II. History/Theory

145. Input: A number in base one enclosed by zero 0 10 :0...0 1 0...0 1 10 :0...0 1 10...0 4 10 :0...0 1 11110...0 10 10 :0...0 1 11111111110...0

146. Output: written in place of the input (same form) 1,>> 0,1 0,>> 1,<< Starting points Starting state II. History/Theory

148. Example: f(x)=x+2 II. History/Theory 1,>> 0,1 0,>> 1,<< 1,>> 0,1 0,>> 1,<<

150. Example: f(x)=x+2 II. History/Theory 1,>> 0,1 0,>> 1,<< 1,>> 0,1 0,>> 1,<< Only one initial state! Only one terminal state! Only one initial state!

152. Example: f(x)=x+2 II. History/Theory 1,>> 0,1 0,>> 1,<< 1,>> 0,1 0,>> 1,<< Relabel states Make the new link

155. Turing Machines are the actual formalisation of what is called algorithms II. History/Theory

157. Instructions are usually listed explicitly starting 'from the top' and going 'down to the bottom': this is what is formally called the flow of control . II. History/Theory

164. Look at each of the remaining items in the list and if it is larger than the largest item so far, make a note of its rank.

168. conditions

169. Loops

171. 3 + 4 * 2 is an expression

172. PRINT “Hello” is not.

174. Algorithm Example: largest number Pseudo-code (http://en.wikipedia.org/wiki/Pseudo-code) max = 0 for ( all i such that 0<i<|L|) { if ( L max < L i ) max = i } PRINT L m ax Loop Condition Assignment Output II. History/Theory Condition : two forms If (boolean expression) expression_if_true If (boolean expression) { expression_if_true }else{ expression_if_false }

181. Java: TRUE= true , FALSE= false

183. Boolean Operators Table II. History/Theory

184. Algorithm Example: largest number Pseudo-code (http://en.wikipedia.org/wiki/Pseudo-code) II. History/Theory PRINT “Hello” If (person has a PhD) PRINT “Dr.” PRINT name PRINT “Hello” If (person is a male) { PRINT “Mr.” }else{ PRINT “Mrs.” } PRINT name Execution for Dr.Pierre: “Hello Dr. Pierre” Execution for Mrs. Bhutto “Hello Mrs. Bhutto” Indentation and brackets are very important!

185. Algorithm Example: largest number Pseudo-code (http://en.wikipedia.org/wiki/Pseudo-code) max = 0 for ( all i such that 0<i<|L|) { if ( L max < L i ) max = i } PRINT m ax Loop Condition Assignment Output II. History/Theory Loop : many forms For (variable in “a finite set of values”) expression While (boolean expression) expression Do { expression } while (boolean expression) In all forms, you have a stop condition

188. Algorithm Example: largest number Pseudo-code (http://en.wikipedia.org/wiki/Pseudo-code) max = 0 for ( all i such that 0<i<|L|) { if ( L max < L i ) max = i } PRINT m ax Loop Condition Assignment Output II. History/Theory Input/Output : many forms Input from keyboard, mice, file, network, parameters Output to screen, file, network, printer, returned values

189. Input/Output: Bad example Avoid interactions II. History/Theory PRINT “Size of the list?” READ size FROM KEYBOARD for ( all i such that 0<i<size) { L i = a random number } max = 0 for (all i such that 0<i<|L|) { if ( L max < L i ) max = i } PRINT L max ON SCREEN Algorithm Interactions List construction

190. Input/Output: Functions f(x) = 3x+2 g(M) = M' such that if M(x,y), M'(0,y) II. History/Theory Name Input Output Name Input Output Type of Input and Output! Guessed usually! Same thing in Pseudo-code!

192. input (max?)

193. output (max?) Function calls Name Input Output Unrelated variables Variables are only visible inside their enclosing block delimited by brackets

194. max = 0 for ( all i such that 0<i<|L|) { if ( L max < L i ) max = i } PRINT m ax Loop Condition Assignment Output Algorithm Example: largest number Pseudo-code (http://en.wikipedia.org/wiki/Pseudo-code) II. History/Theory Index is returned, not the actual value! Example: 31415 Value Printed is 4

195. Yes No Yes No Algorithm Example: largest number Flowchart (http://en.wikipedia.org/wiki/Flow_chart) II. History/Theory Should be explicit here! index = 0 max = index index < |L| ? L max < L index ? max = index index = index + 1 Start End return max Example: 27182 Largest: 3

196. Flowcharts – Common Symbols Symbol Name Terminal Process Flow-line Decision Input/Output Function Beginning or end of a program Flow of logic Calculation or data manipulation Comparison, Question, Decision that determines alternative paths to be followed Input or Output of data II. History/Theory

197. II. History/Theory Algorithm Example: largest number C-code (http://en.wikibooks.org/wiki/Computer_programming) int largest_index(numbers[] t, int n) { int i = 0; int max = i; for (i = 0; i < n; i++) { if (t[max] < t[i]) max = i; } return max; } Data Type List represented as an array Abbreviations: i++ means i = i +1 Statements end with a semi-colon

200. So, given a string of characters, can we prove it is the actual representation of a TM?

201. Given a TM and a string, can we prove that the given string represents the given TM? II. History/Theory

203. Suppose that such a TM machine exists.

204. Consider: boolean trouble( s ) { if ( halt(s,s) == true ) { loop forever; // Implementation? else { return true; } } String representing an algorithm II. History/Theory

206. Consider the string 't' that represents the algorithm trouble()

209. we prove that solving this problem is equivalent to solving the HT problem.

212. Problems with more complex answers are called function problems.

213. The problem itself is distinct from the methods used to solve it, called algorithms.

214. A decision problem which can be solved by some algorithm is called decidable .

220. g(x,y)=x-y -->  x. ( y . x-y)=  x y . x-y; g(3,2)=1--> (  x y . x-y)) 3 2 = ( y . 3-y) 2 = 3-2 = 1

221. g(f(1),f(0)) = f(1)-f(0) = (1+2)-(0+2) = 3+2 = 5 --> (  x y . x-y) ((  x. x+2) 1) ((  x. x+2) 0) Returns a number Returns a function II. History/Theory

223. This equivalence of lambda expressions can not be decided by an algorithm in general

224. Consider: (  x. x x) (  x. x x) --> No reduction!

225. Logic and predicates TRUE :=  xy. x, FALSE :=  xy. y AND :=  pq. p q FALSE, OR :=  pq. p TRUE q NOT :=  p. p FALSE TRUE, IFTHENELSE :=  pxy. p x y II. History/Theory

228. II. History/Theory Functionnal language Example (http://en.wikibooks.org/wiki/Computer_programming) (defun f (n) (if (< n 2) 1 (* n (f (- n 1))) ) ) Only functions Prefix notation Recursive call Inferred!

233. Computer science community regards it as the first and still the best comprehensive treatment of its subject.

234. Bill Gates: &quot;If you think you're a really good programmer... read (Knuth's) book...You should ... send me a resume if you can read the whole thing.&quot; II. History/Theory

238. Space: quantity of information storage required

239. A Complexity Class is the set of all of the problems which can be solved using a certain amount of a certain computational resource. II. History/Theory

241. Alternative algorithm may require less time but more space (or vice versa) to solve a given problem.

243. Sequential time gives a limit to how far the computation can be parallelized. Some steps must be done sequentially because they depend on the results of previous steps. II. History/Theory

244. Practical Complexities II. History/Theory

245. Practical Complexities II. History/Theory

248. Algorithm in 2 n requires 2 100 instructions

249. 2 100 > 10 ^30 instructions, more than 400 millions of years of computation!! II. History/Theory

253. Sorting, Searching, Merging, ...

256. Decision version of the TSP (is there a route with cost < x?)

257. Subset-sum problem (is there any subset of {-2, -3, 15, 14, 7, -10} that sum to zero? II. History/Theory

259. NP: the set of “easy to check” problems

266. Proof by reduction was then used to show than many other problems are NP-C (more than 3000 are known to be NP-C problems)!

270. One of the most important unsolved problems in all mathematics.

271. The Clay Mathematics Institute has offered a USD 1,000,000 prize for a correct solution.

272. 2002: poll of 100 researchers: 61 no, 9 yes, 22 unsure, 8 impossible to prove or disprove! II. History/Theory

276. Still not proven today! II. History/Theory

277. http://en.wikipedia.org/wiki/History_of_programming_languages II. History

280. Interpretation: translate partially, then execute (repeat until the end of the program) II. History/Languages

281. Compilation vs Interpretation (http://en.wikipedia.org/wiki/Interpreted_language http://en.wikipedia.org/wiki/Compiled_language) Source file Executable file II. History/Languages Operating System X=20; while(X > 0) { PRINT X; X := X-1; } 011001010110110110100101011010101011001100110010101011011001010100011000001110101010101001 Compiler Interpretor X=20->0110 While->1010 Executable file running

285. Cons: slow, lack of checks II. History/Languages

291. Based on the Church  -calculus II. History/Languages

294. hardware makes no distinction between memory addresses, instruction code, characters, integers and floating-point numbers. II. History/Languages

296. The underlying implementation (typically) uses an array of characters

301. Optimisation for runtime speed

303. Illusion that the code is safe

305. Edit-compile-test-debug cycle reduced

306. Generic constructions (eval function over anything)

308. Strong vs Weak Typing II. History/Languages

310. Integer, booleans, characters, floating point numbers

316. Any language in the world!

317. Supported by new OS and languages II. History/Languages

319. so, in a base b, we have (a n ...a 1 a 0 .c 1 c 2 ...) b = a n .b n +...+a 1 .b 1 +a 0 .b 0 +c 1 .b -1 +c 2 .b -2 +...

320. (0.1) 10 =(1) 10 /(10) 10 =(1) 2 /(1010) 2 =(0.000110011001100 ....) 2 =(0.00220022...) 3 =(0.01212...) 4 ...

325. We lose +0.5 and -0.5 IEEE 754 Standard Example Problems & Solutions II. History/Languages 2 1 3 4 5 6 7 1.5 1.25 1.75 2.5 3.5 0.875 0 0.75 0.625 -0.625

330. Floating Point Operations/second (Flops) is a standard metric of processor performance.

331. 2006: IBM Blue Gene: 65536 Dual-Processor (PowerPC ) 360 TeraFLOPS! Problems with the representation of real numbers II. History/Languages

333. a : is an integer representing a RAM cell address

336. char c = 'A'; char* pc = &c; *(pc+1)='C'; *((int *) (pc)) = 'D'; &pc &c *pc = 'B'; Using Pointers (in C) '&' == &quot;address of&quot; II. History/Languages 65 ? ? ? &c 66 67 ? ? &c 65 ? ? ? 0 0 0 68 &c 66 ? ? ? &c

339. char[] c = s; *(c+1) = '3'; printf(s); --> H3llo World II. History/Languages

343. Still widely used but no more learnt II. History/Languages

345. UNIX Systems (and Linux) are written in C

349. Ariane space launcher II. History/Languages

351. Claim to be an OO Language ;-)

352. Widely used because of Microsoft adoption

353. Windows (95, 98, NT, XP) is written in C++

355. Design by contract (software quality) II. History/Languages

357. Widely used (smartcards to supercomputers)

359. Similar to Java on many aspects II. History/Languages

362. II. History

365. Even if not required, a computer system usually has an operating system. II. History/OS

371. Managing storage spaces

372. Managing devices II. History/OS

377. Operator groups jobs into batch and enter them for execution

382. Many ideas of current operating systems comes from it!

384. He developed a smaller Multics version called Unics, that should do only one thing, but do it well. II. History/OS

386. Received the prestigious ACM Turing Award

389. Commercial failure for IBM, Sun, Bell, ... and Microsoft! II. History/OS

390. Unix Wars II. History/OS

392. Paul Allen and Bill Gates developed a BASIC interpreter for the Altair, and then formed Microsoft.

394. Color graphics, open architecture, floppy disk drive II. History/OS

397. Open architecture

398. Uses Intel 8088 processor

400. Digital Research refused to provide CP/M to IBM in 1980 II. History/OS

403. It requires power --> faster CPU, bigger RAM, ... II. History/OS

411. Virus-like licence

412. You can sell a GPL software (Redhat, Suse, ...) II. History/OS

415. Editor: GNU Emacs

416. All other parts (shell, libraries, GUI, ...)

417. A lot have been done but, the kernel (Hurd) is the only piece that is missing... II. History/OS

419. He wrote a kernel, using all the GNU tools

423. Installing, upgrading, removing softwares

425. LiveCD: Knoppix, Mandrake-CD

426. Stability: Debian

427. Source based: Gentoo II. History/OS

429. NetBSD (Portable)

434. CD-ROM

436. Any informations (/proc on Linux) II. History/OS

445. File System Issue Example: External Fragmentation (http://en.wikipedia.org/wiki/Fragmentation_(computer)) Remove C,E After many operations (Create, Remove): Leads to performance problem: reading the red file requires 4 movements. Hard Drives are 1,000,000 times slower than CPU! II. History/OS A B C D F E A B D F Create: G = G 1 G 2 + A B G 1 D F G 2

448. Works very well when the free space available is above 20% II. History/OS

452. II. History http://en.wikipedia.org/wiki/Computer_networking

454. Theory to describe algorithms

455. Languages to write algorithms

463. 1940 George Stibitz used a teletype machine to send instructions from Dartmouth College in New Hampshire to his Complex Number Calculator in New York

464. 1960-1970 Kleinrock, Baran and Davies had independently conceptualized and developed network systems consisting of datagrams or packets that could be used in a packet switching network between computer systems. II. History/Network

466. Special type of computers will take care of the packet switching on the behalf of end-users one (big mainframe at that time) II. History/Network

468. SRI (in Stanford),

469. University of California at Santa Barbara,

472. and others... II. History/Network

473. ARPANet II. History/Network

479. Some companies either helped in research project or provided services (e.g.: HP)

480. They asked for connections and they had!

483. The Growth of Internet The Exponential Growth started thanks to the WWW II. History/Network

489. Web Browsers War (http://en.wikipedia.org/wiki/Browser_wars) II. History/Network

491. Even if until IE v4.0, Netscape was by far superior, Microsoft was enlarging its market share automatically after each OS installation! II. History/Network

493. Microsoft decided to provide for “free” IIS (Web Server) with server version of Windows

502. Smart “unbiased” algorithm (PageRank)

510. Newsgroup: discussion in forums

511. FTP: File Transfer Protocol

512. WWW: World Wide Web

513. Search Engines

514. P2P: User to User Data Exchange

516. Google is the leader (Microsoft Challenger?) II. History/Network

518. Within each layer, one or more entities implement its functionality.

519. Each entity interacts directly only with the layer immediately beneath it, and provides facilities for use by the layer above it.

520. Protocols enable an entity in one host to interact with a corresponding entity at the same layer in a remote host. II. History/Network

522. Internet (TCP/IP) does not!! II. History/Network

523. OSI & TCP/IP II. History/Network

524. Layers at work Abstraction: Communication from process to process Implementation: Communication from layer to layer II. History/Network

525. Layers at work Example: UDP Application Layer Transport Layer Network Layer Link Layer II. History/Network UDP Data UDP Header IP Data IP Header Frame Header Frame Trailer Frame Data

526. Internet Topology (2003-11-23) II. History/Network

527. Network Topology (http://en.wikipedia.org/wiki/Network_topology) II. History/Network

530. IP implementation?

533. IPv6 address: 128 bits (5×10 28 for each 6.5 billion people)

536. Taking the leadership?! II. History/Network

537. III. Conclusion

539. Hardware has been designed to help

540. Theory were needed to understand hardware

541. Languages were required to ease the commanding of hardware

542. Operating Systems were designed to manage hardware and to make it appears a single unit

543. Networking was set up to share the access to costly hardware. III. Conclusion