NASS 2019 P1

Name: .............................................................................. Register no: ............. Class: ...... NGEE ANN SECONDARY SCHOOL O PRELIMINARY EXAMINATION COMPUTING 7155/01 Paper 1 Written 23 August 2019 2 hours Candidates answer on the Question Paper. No Additional Materials are required. Instructions to Candidates Write your name, register number and class at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams, graphs or rough working. 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. Checked by student: _____________________ Date: _________ This document consists of 16 printed pages and 0 blank pages. For Examiner’s Use Marks /80

2 NAS/2019/Prelim/4E/7155/01 1 (a) Convert the binary number 11001011 into a denary number. Show your working. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [2] (b) Convert the denary number 173 into a hexadecimal number. Show your working. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [2] (c) The MAC address of a device is shown below. Fill in the blanks below to indicate what the two groups of numbers represent. 00:B3:A9:12:C9:31 [2] (d) An IT manager is trying to trace if the device in (c) had gained unauthorized access to the company’s network. Based on the log files of the network, the last 4 bits of the unauthorized device’s MAC address in binary form were identified to be 0111. Check and state if the above device was the unauthorized device. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [2]

3 NAS/2019/Prelim/4E/7155/01 2 (a) Information is stored in a computer in units known as bits and bytes. Describe what is meant by a bit and a byte. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [1] (b) Convert the following amounts of data in the stated units. (i) 2 450 000 000 B = ______________________ GB (ii) 2 KiB = ______________________ B [2] (c) Jason wants to set up a simple network at home to connect his laptop and smartphone to his wireless printer. He has a wireless router and a modem to provide Internet connectivity to all the devices. In the space below, draw a simple diagram, with labels and connecting lines, to show how all t