SPSS 2020 Computing P1

READ THESE INSTRUCTIONS FIRST Write your name, class, index number in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Approved calculators are allowed. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. You should show all your working. The total number of marks for this paper is 80. Parent’s Signature : ____________________________ Date: ____________________________ Remarks (if any) : For Examiner’s Use Marks /80 Total % This document consists of 11 printed pages including this page. ST. PATRICK'S SCHOOL PRELIMINARY EXAMINATIONS 2020 SECONDARY 4 EXPRESS NAME CLASS INDEX NUMBER COMPUTING Paper 1 Written 7155/01 20 August 2020 2 h Candidates answer on the Question Paper. No Additional Materials are required.

2 1 (a) Convert the binary number 0101 1111 into its hexadecimal value. [1] (b) Convert the positive whole denary number 462 into a 12-bit binary number. Answer: [2] (c) Describe how the hexadecimal number 8A is converted into its denary value. Give the denary value in your answer. Description: Denary value: [4]

3 2 The following diagram shows five network terms and six descriptions. Draw a line from each network device to its best description. Network Devices Description Bridge A device that constructs a single network by connecting two similar networks together Router A device responsible for modulation and demodulation Network Interface Card (NIC) A device that provides the hardware interface to enable the transfer of data between a device and a network. Modem A device that extends the distance a signal can travel Hub A device that forwards packets between separate networks A device that transmits received packets to all connected devices [5]

4 3 The following pseudo-code algorithm validates the age of a user. 1 2 3 4 5 6 7 8 9 10 11 is_valid = False no_of_users = 0 CURRENT_YEAR = 2020 WHILE is_valid = False OUTPUT “Enter your birth year: ” INPUT birth_year IF CURRENT_YEAR – birth_year >= 18 THEN is_valid = True no_of_users = no_of_users + 1 ENDIF ENDWHILE (a) The algorithm is tested using the following three numbers as input: 2006, 2000. Complete the trace table for the algorithm. birth_year is_valid no_of_users [3] (b) State whether is_valid is a variable or a constant. Give a reason for your choice. [2] (c) Identify the data validation technique used in the algorithm.