This paper is not to be removed from the Examination Halls

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1 ~~IS1168 ZB d0 This paper is not to be removed from the Examination Halls UNIVERSITY OF LONDON IS1168 ZB BSc degrees and Diplomas for Graduates in Economics, Management, Finance and the Social Sciences, the Diplomas in Economics and Social Sciences and Access Route Introduction to Computer Systems Architecture and Programming Wednesday, 27 May 2015 : 10:00 to 13:00 Candidates should answer FOUR of the following EIGHT questions: TWO from Section A and TWO from Section B. All questions carry equal marks. PLEASE TURN OVER UL15/0278 Page 1 of 5

2 SECTION A Answer two questions from this section. 1. In 1945 John von Neumann wrote a famous Report in which he proposed ideas for an architecture for a computer called the EDVAC. The development of the EDVAC is viewed as an important milestone in the development of computer technology. Explain and discuss the significance of von Neumann's ideas and the development of the EDVAC for the field of computer architecture. (15 marks) Apart from the ideas realized in the EDVAC computer what do you consider to be the most significant advancement in the field of computer architecture? Justify your answer. 2. Boolean Logic was created by George Boole, an English mathematician and philosopher, in the 1800s. (d) (e) Explain briefly what is meant by Boolean Logic, and its relationship with binary numbers operations. Logic gates circuit design is based on the ideas of Boolean logic. Describe the 4 main logic gates and provide gate symbols for each of them. A half adder can be created by linking an XOR gate with an AND gate. Using these gate symbols draw a half adder. Describe, using a truth table, how a half-adder circuit can support binary addition. (2 marks) Describe the limitations of the half-adder for binary addition and, using gate symbols, draw a circuit which overcomes these limitations (known as a full adder circuit). (7 Marks) UL15/0278 Page 2 of 5

3 3. Within many modern computers a hard disk drive is used to store different types of information as different patterns of magnetization (representing different binary states) on the rapidly rotating magnetically coated surface. Describe how we measure the storage capacity of a hard disk and describe two ways in which text might be represented on the hard drive storage. Assume that an average journal is 60 pages long, and that each page contains 700 words. Calculate roughly how many journals can be stored on a 400Gb hard drive (assume 1000 bytes to a kilobyte). (d) Describe how images may be represented on the hard drive storage. Distinguish between black and white images and colour images. Convert the numbers and into binary numbers. Then use these binary numbers to show how binary addition is carried out in the binary number system. Make sure you show and explain the steps you are taking to get to your results. (e) Describe two ways in which negative numbers can be represented in binary. 4. The scheduling and coordination of program execution is one of the main tasks of a computer's operating system. Explain how the scheduler and the dispatcher support these operating system tasks. Semaphores help control the access of multiple processes to one or more common resources. Explain what a semaphore is and, with the help of an example, explain how a semaphore can avoid scheduling problems. How does a semaphore deal with more than one resource of the same type? Within a computer system several processes have to make use of the same printer. Suggest an appropriate scheduling method for this scenario and justify your choice. (3 marks) UL15/0278 Page 3 of 5

4 SECTION B Answer two questions from this section. 5. Within Java a class can be considered as a "blueprint" from which individual objects are created through instantiation. Consider the class "library book". i. Suggest 4 attributes and 2 methods for the library book class. (2 marks) Create a class for your library book using the Java Programming Language. Include explanatory comments in your code. Explain the underlying ideas of object-orientation. Use the class created in to illustrate how Java implements the ideas of object-orientation. Java includes a large library of pre-written classes (The Java Class Library). It has been argued that this extensive Class Library is a main reason why Java is so popular. Do you agree? Justify your answer. 6. Repetition is an important way to allow operations to be repeated on a large number of different data items. A shop sells a variety of different products, each at different prices. The shop needs a program that will operate as a (basic) cash-register (till). The program should: - ask for the price of each item - ask, for each (new type of) item, how many the customer wants to purchase - record how many items the person is purchasing in total - stop asking for the price of each item when the user enters a price of -1 (a negative number) - then display the number of items sold, and the total price for all the items sold. Describe nested loops and explain why they are important, using an example of a program which might need a nested loop (you do not need to provide any code). UL15/0278 Page 4 of 5

5 7. The if statement is used to change the flow of control within a With the help of a simple example, explain how the if statement can change the flow of control within a Java Consider a program called CurrencyConversion that offers the user the choice of converting US Dollars into British Pounds or the other way around. (You may assume that 1 US Dollar = Pounds.) 8. In a Java program each variable has to be of a particular data type. The data type can be viewed as a classification of the type of data that the variable can hold. With the help of examples describe the difference between primitive and reference data types. An array is a data type that is useful for storing a range of related values. Develop a program (that makes use of a 2-dimensional array) for the scenario below. A group of 80 athletes is participating in a triathlon. The triathlon involves a 1000m swim, a 25km cycle, and a 5km run. The required program should - ask for, and record, the separate times needed by each athlete for his/her swim, cycle and run (in seconds). - determine and display the overall winning time and the index-number of the best overall performing athlete (the winner). END OF PAPER UL15/0278 Page 5 of 5

This paper is not to be removed from the Examination Halls UNIVERSITY OF LONDON

~~IS1168 ZA d0 This paper is not to be removed from the Examination Halls UNIVERSITY OF LONDON IS1168 ZA BSc degrees and Diplomas for Graduates in Economics, Management, Finance and the Social Sciences,