SIR MICHELANGELO REFALO

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SIR MICHELANGELO REFALO SIXTH FORM Annual Exam 2014 Name: COMPUTING ADV 2 ND 3hrs Section A This question is Compulsory of 16 marks Consider carefully the following 2 classes and answer the related

1 SIR MICHELANGELO REFALO SIXTH FORM Annual Exam 2014 Name: COMPUTING ADV 2 ND 3hrs Section A This question is Compulsory of 16 marks Consider carefully the following 2 classes and answer the related questions below: public abstract class SuperClass{ public SuperClass(){ System.out.println( super class: constructor ); public void methodx(){ System.out.println( super class: methodx ); public class SubClass extends SuperClass(){ static int n=0; int id; public SubClass(int num){ super(); System.out.println( sub class: constructor ); id = ++n; public void methoda(int num){ System.out.println( sub class: methoda + num); System.out.println( line 2 sub class: method + id); Page 1 of 11

2 public void methoda(){ System.out.println( sub class: methoda ); System.out.println( line 2 sub class: method + id); a. What will be the output when the below code is executed: public static void main(string[] gahan){ SubClass sub = new SubClass(3); sub.methoda(4); sub.methodx(); [4 marks] b. Explain why the code will not be executed. Modify is so that it will execute and display the output. public static void main(string[] kokroces){ SuperClass sup = new SubClass(3); SubClass sub2 = superclass; [marks 4] c. What will be the output when the below code is executed: public static void main(string[] miskinilgemel){ SubClass sub = new SubClass(3); SubClass sub1 = new SubClass(3); SubClass sub2 = new SubClass(3); sub.methoda(69); sub1.methoda(); sub2.methoda(); [marks 4] Page 2 of 11

3 Section B Answer ONLY 7 questions of 14 marks each. Question 1 Digital Logic A box contains red and white balls. Four balls are drawn in succession from the box. If the outcome of this event results in three or four of the balls drawn being of the same colour, it is called a success. Otherwise it is a failure. a. For the four balls drawn, named A, B, C, D work out the logic truth table that has an output F. 1 for success and 0 for failure. [7 marks] b. Set up a suitable Karnaugh map [3 marks] c. Draw the Logic circuit. d. Use Boolean algebra to show that ((XW) + (XZ) ) = XWZ Page 3 of 11

4 Question 2 Computer Architecture a. Name the three main buses of a computer. State and explain in detail how the bus size can affect computer performance and how. [3 marks] b. Differentiate between Synchronous and Asynchronous data communication. c. Explain the characteristics of SRAM and DRAM in regards of computer s memory. d. The computer has to communicate with its IO (input or output) using two different IO addressing. Name and explain these 2 different IO addressing. e. With regards to speed, width and function compare and contrast AGP, PCI and PCI- X. f. What is the use of the DMA? [1 mark] g. With regards to CPU instruction set compare and contrast RISC and CISC. [2marks] Page 4 of 11

5 Question 3 Assembly Language a. An instruction of assembly is made into 2 parts. Name the parts and state the use of each part. b. Some registers are of 2 or more bytes having High order bits and low order bits. What are high order and low order bits in relationship to assembly instructions? c. Below is part of main memory: Mem Address Data What are the contents of the four memory addresses after the execution of the following instructions? MOV R1, #02; put 2 in R1 MOV R2, 401; put 401 in R2 ADD R2, R1; add R1 to R2 result in R2 MOV (R2), R1; put R1 to memory, using R2 as a register indirect memory address d. Explain in detail the four stages of the assembly process. [4 marks] e. State the differences between: cross assembler, macro assembler, and meta assembler.[4 marks] Page 5 of 11

6 Question 4 Operating Systems a. What is the difference between the following types of OSes: Online, Real-Time and network? b. Explain the 3 states a process can be during it execution. In case the OS is single task not multi task will there be different states for a process? c. Name and explain 2 different CPU scheduling algorithms. d. What is deadlock and how can the OS detects or avoid? e. Contiguous Memory can be partitioned using fixed or variable partition. Explain fixed and variable partition in relationship to contiguous memory. Mention also the drawbacks in each method. f. What are pages and page frames in relationship to non-contiguous memory? What is the use of the PMT table? [2marks] g. Files on disc can be stored using: o Contiguous blocks o Linked blocks o Indexed Explain the above types of storage files systems. Page 6 of 11

7 Question 5 Networking and Communications a. When data is being transferred from one point to another in a network, transmission errors may arise. Describe 2 commonly used methods that help detect such errors and state how errors are corrected b. In detail explain the OSI model. c. What is the TCP/IP protocol and where is it used? d. Differentiate between bit rate, baud rate and bandwidth? e. What are modems and explain the following modulation in terms of modems: amplitude frequency phase pulse coded (PCM) f. Compare and contrast TDM with FDM in terms of multiplexing. g. In terms of media access methods with is CSMA/CD? Page 7 of 11

8 Question 6 Language Translators a. What are the differences between formal and natural languages? Why cannot natural languages be used in order to describe the syntax of a PL (programming language)?[2marks] b. Name two different ways how we can represent the syntax of a PL? Give appropriate examples. c. Write the syntax using BNF for a valid Maltese post code (e.g. KIK letters followed by 4 numbers) d. What is the difference between syntax and semantics? e. What is parsing and in what stage of compilation does parsing occur? f. Write the stages of compilation and explain in detail each stage. g. If the rules of precedence are ignored, this expression, W Z * X, can be evaluated in 2 different ways. Use a BST to evaluate/parse the possible combinations of this expression. Also state why this expression is Ambiguous. Page 8 of 11

9 Question 7 Systems Analysis and Design a. Compare and contrast RAD with waterfall? b. What is UML and how can class diagrams help in designing a computer system? [2 marks] c. DFDs are very useful in System analysis. What are DFDs and state their use. d. HIPO and JSP are two algorithm representation forms. Explain these two forms and give a simple example of each. [3 marks] e. Name three types of software maintenance. [3 marks] f. Differentiate between White box Testing and Black Box Testing. Page 9 of 11

10 Question 8 Databases A shipping agency ShipAnywhere processes and has information about the current location of each shipped item. Shipped items are tracked using a special tracking information system. Item shipped are characterized by Item ID (unique and not null), dimensions, weight, insurance value, destination address and delivery date. Shipped item are inputted into the system at the company headquarters/centres. Company centres are characterised by ID, address and type. Shipped items are delivered either by flight or truck. These transportation events are characterised by Schedule ID, type (flight or truck) and delivery route. a. Use a standard notation to represent the entities described above. Clearly identify the primary key and attributes for each table: Entity (attrb 1, attrb2 attrbn) [4 marks] b. Draw and E-R diagram representing the above database with its relationships. [4 marks] c. SQL can be categorised in 3 sections in Databases. Name and Explain the 3 categories.. [6 marks] Page 10 of 11

11 Question 9 Data Structures and Algorithms a. Show and describe, step by step, how the quick sort algorithm sorts the flowing list of integers. (show the steps in a table) [4 marks] 66,97,89,10,92,8 b. State the complexity of this algorithm in Best case, average and worst case d. What can be a worst case scenario for quick sort. c. A binary search tree is a special data structure. Explain in detail and using examples the conditions required to make a correct BST. e. Use a BST below to traverse it and output the data in pre-order, post-order and inorder. [4 marks] Page 11 of 11

SIR MICHELANGELO REFALO SIXTH FORM

SIR MICHELANGELO REFALO SIXTH FORM Annual Exam 2016 Subject: Computer Advanced Time: 3 hours 1. System modularisation refers to dividing a system into smaller pieces explain a. What makes a good module?