Outline of Unit 16: Realistic expectations

1. Outline of Unit 16:Realistic expectations • The digital computer, the success of the twentieth century • Reaction to the rise of ICT • What can go wrong with computer applications? • What computers cannot do • What computers should not do • Ethics and computing Arab Open University - Riyadh

2. The digital computer, the success of the twentieth century The invisible computer. In the same way that electric motors have disappeared from our immediate awareness, computers – in the form of microprocessors and their associated sensors, actuators and displays – are embedded inside information appliances. Interesting tools: the hand-held personal GPS navigators. Massively Distributed Computing: The spare processing capacity of relatively small personal computers, when combined appropriately over a network, can be used to solve major problems.

3. Moore’s law • Gordon Moore, one of the founders of microprocessor manufacturer Intel and later its chairman, predicted in 1968 that he expected ‘a doubling of transistor density [...] every year’. • Since Intel sold its first microprocessors in 1971, the semiconductor industry has managed to double the number of transistors on a chip roughly every 18 months, right up to the present time.

4. Being driven to abstraction • Perhaps the most explicit example of abstraction and a ‘layered approach’ to managing complexity is the Open Systems Interconnection seven-layer model for handling the communication of information across networks.

5. The OSI Model

6. OSI model Layers Layer 1. Physical Layer:Defines the physical [hardware level] implementation and the electrical [signal level] implementation of the bus; network cabling, connector type, pin-out, physical data rates, maximum transmission distances, and data transmission encoding. The material about OSI layers is additional (not from M150).

7. OSI model Layers Layer 2. Data Link layer:Frame format, transmitting frames over the net [additional bit/byte stuffing, start / stop flags, checksum, and CRC]. CAN bus, ATM, StarLAN, LocalTalk and HDLC are layer 2 protocols. Different network and protocol characteristics are defined by different data link layer specifications.

8. Layer 3. Network Layer:Provides address assignment, and packet's forwarding methods. Protocol Data Unit [PDU] is called a Packet at this layer. This layer responds to service requests from the Transport Layer and issues service requests to the Data Link Layer. OSI model Layers

9. Layer 4. Transport Layer:Provides transfer correctness, data recovery, and flow control. TCP is a layer 4 protocol. Protocol Data Unit [PDU] is called a Segment at this layer. This layer responds to service requests from the Session Layer and issues service requests to the Network Layer. OSI model Layers

10. Layer 5. Session Layer:Establishing a communication session, security, authentication. NetBIOS is a layer 5 protocol. Protocol Data Unit [PDU] is called Data at this layer. This layer responds to service requests from the Presentation Layer and issues service requests to the Transport Layer. OSI model Layers

11. Layer 6. Presentation Layer:Determines how computers represent data [ASCII, GIF..]. Protocol Data Unit [PDU] is called Data at this layer. This layer responds to service requests from the Application Layer and issues service requests to the Session Layer. OSI model Layers

12. Layer 7. Application Layer:The highest layer. Generates or interprets data, may also provide encryption or decryption. Applications using the network learn how to send a request, how to specify a filename over the net, how to respond to a request. OSI model Layers

13. Outline • The digital computer, the success of the twentieth century • Reaction to the rise of ICT • What can go wrong with computer applications? • What computers cannot do • What computers should not do • Ethics and computing

14. The responses of individuals The optimists:Respond in a wholly positive, enthusiastic way, seeing machines as freeing humans from drudgery as well as providing them with enhanced capabilities. The pessimists:For them, any use of computers is potentially negative. They think that technology will increase power of surveillance of individuals by the state or other powerful organisations. The realists:They are able to appreciate that the computer can act as a tool to enhance human activities but that it is limited in its potential by its (currently) digital nature and by our limitations in understanding our problems and ourselves.

15. Outline • The digital computer, the success of the twentieth century • Reaction to the rise of ICT • What can go wrong with computer applications? • What computers cannot do • What computers should not do • Ethics and computing

16. What can go wrong with computer applications? Dependence and risk Hardware failure Software crisis (the Y2K exemplary) Inadequate requirements Incorrect coding Infeasibility of testing

17. What can go wrong with computer applications? Inadequate models Over-maintained code: Every time changes are made to a system they are likely to add to the complexity of the system, to introduce new errors, and to make subsequent maintenance more difficult.

18. Inadequate requirements specification The Swing project This is how the customer explained it

19. This is how the project Leader understood it

20. This is how the engineer designed it

21. This is how the programmer wrote it

22. This is how the sales executive described it

23. This is how the project was documented

24. These are the installed components

25. This is how the customer was billed

26. This is how the helpdesk supported it

27. This is what the customer really needed

28. Outline • The digital computer, the success of the twentieth century • Reaction to the rise of ICT • What can go wrong with computer applications? • What computers cannot do • What computers should not do • Ethics and computing

29. What computers cannot do Not everything is quantifiable Limitation on accuracy of representation Models are only approximations to reality Humans don’t work according to (explicit) rules Advanced e-thinking: computer playing chess. Can computers understand natural language?

30. Outline • The digital computer, the success of the twentieth century • Reaction to the rise of ICT • What can go wrong with computer applications? • What computers cannot do • Whatcomputers should not do • Ethics and computing

31. What computers should not do They should not: Remove humans from the control loop Replace human knowledge and experience Take the human role

32. Outline • The digital computer, the success of the twentieth century • Reaction to the rise of ICT • What can go wrong with computer applications? • What computers cannot do • What computers should not do • Ethics and computing

33. Ethics and computing Ethics in the context of ICT ‘Ten Commandments of Computer Ethics’ Terms of Service agreement Ethics and computing profession professional morality: commitment to public well-being. software development morality: commitment to ensuring quality in both process and product, arising from the adoption of ‘best practice’. The persuasive computer The Golden Rule of Persuasion: The creators of a persuasive technology should never seek to persuade a person or persons of something they themselves would not consent to be persuaded to do.