1. MATSEC Past Papers May 2010 Paper 1 Paper 2A

2. What is the difference between each of the following pairs of items? Syntax Error Caused by forgetting certain codes and statement structures Not obeying the programming language’s rules The compiler will find these errors Ex. System.out.plintln(“hi”); Logical Error A mistake found in the actual design of a program Use of the wrong mathematical operation Found by gaining the wrong results Ex. Average = 10+11+2/3 10

3. What is the difference between each of the following pairs of items? Byte A byte is a group of 8 bits Word A word is a group of bits that are handled as a unit by the instruction set of the CPU Assembler Assembler translates Assembly language into machine code. Compiler Compiler translates a high level language source code into executable code

4. What is the difference between each of the following pairs of items? Integer data type Can only store whole numbers Real data type Can store numbers with decimal places CAM computer aided manufacturing Processes models from CAD and manufactures them using machines CAD computer aided design 3D sketches of an object

5. Give one reason why: Passwords are required To prevent unauthorised access to files and other resources 4 The Data Protection Act as established To protect sensitive data of the individual and prevent unauthorised distribution and access of data. Backups are made So that if the original files are corrupted they can be replaced with their backups. Software is copyrighted it’s the right of the author which states that software cannot be copied or modified

6. Fill in the missing terms; The ALU performs arithmetic and logical operations 5 A character code that is widely used in computers is ASCII or UNICODE Two types of optical storage media are CD and DVD A computers main memory stores both data and addresses A parity bit is an extra bit that is added to a byte to help detect errors

7. Which communication medium transfers data as pulses of light? Fibre optic cables 1 Telephone line Cable line Satellite List another 3 types of communication media 3

8. Identify Two advantages and two disadvantages of using a wireless network at home 4 Advantages: Computers can be placed anywhere There is no need for cables. Disadvantages: More security risk, Sometimes signal doesn’t reach all places.

9. A computer currently has 512MB of main memory and the owner wishes to upgrade it to 1 GB. If the memory chips available have a capacity of 256 MB, how many of these chips are needed? 2 512 / 256 = 2 Mention two advantages of having a larger memory The computer will be much faster Multitasking will not slow down the computer 2

10. Describe a problem for which a computer simulation would be a suitable method of solution and explain why a computer simulation would be the most suitable method in this case 3 Training an airplane pilot, since an airplane is dangerous to fly without any experience since it can cause a lot of damage, the pilot has to be trained in a safe environment first. (Other simulations: space exploration, soldier training)

11. Briefly describe two methods of validating data and for each method give an example of invalid data 4 Method 1: Range check, if a month is inputted, it has to be checked if it’s between 1 and 12. Method 2: Check digit, if a number is inputted (such as credit card number) a special algorithm is carried out and it checks if the inputted number is valid or not.

12. Mention 3 types of documentation that are produced during software development and state why each is needed 6 User: helps the user on how to use the basic functionality of a program. Technical: helps the technician solve problems using troubleshooting and how to conduct any changes to the program. Programmer: Helps programmer understand the program through graphical representations such as flowcharts and comments.

13. Write the binary equivalent of the hexadecimal number 4A 2 4A = 10 84218421 01001010

14. If the ASCII code equivalent to the letter A is 65. Which letter does the binary number 01001010 represent 2 65666768697071727374 ABCDEFGHIJ J 01001010 = 74

15. What is the largest number that can be stored in an 8-bit register 2 1286432168421 11111111 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255

16. Consider the terms below : Consider the terms below : flash memory, scanner, mouse, modem, RAM 4 Which of the above allows digital data to be transmitted over telephone lines? modem Which of the above is a form of non-volatile storage? Flash memory Which of the above can translate drawings and photos into digital format? Scanner Which of the above is a form of volatile storage? RAM

17. Consider the truth table below ABCXYZ 000001 001010 010001 011010 100001 101010 110101 111110

18. Draw the logic circuit corresponding to the truth table 9 A B X C Y Z

19. Paper 2 A We will be doing a class correction of paper 2A together tomorrow so please bring this paper worked out