Name: Index: Class: ST.FRANCIS SECONDARY SCHOOL SLIEMA HALF YEARLY EXAMINATIONS SENIOR 3 COMPUTER STUDIES TIME: 2 hours The use of CALCULATORS is NOT ALLOWED!! Answer ALL questions!! 1: The following diagrams show two different signal waves. You have to write down the name of each wave in the space provided below. (2 marks) 2: Underline the correct answer: (3 marks) a. (Analogue / Digital) data is represented as some continuously changing data. b. Computers are (Analogue / Digital), because they consist of discreet units called (bits / registers) that are either on or off. 3: a. Explain the difference between Main Memory and Backing Storage: (2 marks) Senior3 - Computer Studies Page 1
3: b. Draw a simple diagram to show how a computer system is organised. (7 marks) Draw arrows to show the flow of data. Make sure you include the following words in your diagram: Input device Output Device Backing Storage CPU Main Memory In your diagram show clearly the flow of data between the input, output, backing storage and the CPU. 4. Mark with a in the appropriate box stating whether the following are True or False: (5 marks) 1 The truth table for the OR function shows one everywhere except where all the inputs are zeros. 2 The system software which helps the user modify the hardware is called the application software. 3 Modern PDAs have a touch sensitive screen. 4 10 10 can be represented as 1010 2. 5 The output from a plotter is an example of a softcopy. 6 Scanning technology is used to read the numbers at the bottom of cheques 7 Mouse, touch screen and touchpad are all examples of OCR devices. 8 In Computer Logic, the NOT Gate inverts the input given. 9 The CU performs Arithmetic and Logic Operations. 10 An inkjet printer is a very popular device for generating hardcopies. True False Senior3 - Computer Studies Page 2
5. a. What is the maximum number that may be represented in an 8 bit Register? Give your answer in both binary and decimal. (2) b. What does the abbreviation ASCII stand for? (1) c. Given that an ASCII-type coding system codes the (capital) letter A with the decimal number 65, what binary number is used to represent the (capital) letter G? (2) d. A character set consists of 200 different characters. What is the minimum number of bits that can be used to represent this character set? Why? (2) e. Why is it important to have a standard character code like ASCII? (2) 6: This question is about INPUT & OUTPUT Devices a) Compare and contrast an MICR and an OMR (1) b) Compare and contrast a hardcopy and a softcopy (1) c) Compare and contrast an impact printer and a non-impact printer (1) d) Give one use for each of the following: (4) Graphics Tablet Trackball ICR Bar Code Reader Senior3 - Computer Studies Page 3
e) What are Braille Printers? (1) f) A training institute is considering the implementation of a new method of capturing students answers in an examination. (2) I. Suggest a suitable input device for such a situation II. Name one type of exam question that would be suitable for grading using such a device: 7. Consider the following logic circuit: A B C X Y Z 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 1 0 1 0 1 1 0 1 1 1 1 1 a) Complete the truth table for all possible inputs of A, B and C. (3) b) What is the missing logic gate?. (2) 8. Use four of the following words to complete the paragraph below on output devices. (4) softcopy vector raster resolution hardcopy Monitors and printers form their output as an array of dots and therefore are called devices. The quality of the image / print depends on the of the device. A monitor produces a of the output while a printer produces a. Senior3 - Computer Studies Page 4
9. For each of the following devices state if it is an Input or an Output device: (4) a b c d e f g h Braille Keyboard Eye Sensor Readers Graphics Tablet LCD Projector VDU Digital Camera Touchpad Light pen 10. Fill in the table below to obtain the conversion of each number in binary (8 bit), hexadecimal and decimal. (6) Binary Hexadecimal Decimal 1 0 1 1 0 0 1 1 1A 200 Working: Senior3 - Computer Studies Page 5
11. Write in full the following abbreviations: (5) 1 GUI 2 DOS 3 GIGO 4 ALU 5 RAM 6 DPI 7 PDA 8 OCR 9 CRT 10 FPD 12. Explain each of the following and where possible support your answer with an example: (10) a. Operating System: b. Application Software: c. Data is not Information. Explain: d. Information retrieval: e. Peripheral Device: Senior3 - Computer Studies Page 6
f. The function of the ALU: g. The function of the CU: h. The function of the MU: i. Truth Table j. Logic Circuit 13. Answer the following questions: (6) a. A modem is both an analogue-digital converter and a digital-analogue converter. Explain what a modem is. b. We have a variety of pointing input devices, depending on the situation in which it is being used. Explain giving examples. c. Which of the following is an incorrect hexadecimal number? And why? AB 16 23 16 9F 16 4H 16 14. Consider the following logic circuit: What is its Boolean expression? (3) Senior3 - Computer Studies Page 7
15. How many bits are required to store the following number representations? The first one has been done for you. (5) Item Decimal Number Bits Required Example: Days in a year 365 9 bits Days in a week Months in a year An on/off switch Seconds in 3 minutes Days in 2 years 16. Draw the logic circuit and the truth table for the expression: (2;2) X = NOT (A AND B) OR C Senior3 - Computer Studies Page 8