MSHS 2018 P1 solution

Class Index Number Name MARIS STELLA HIGH SCHOOL PRELIMINARY EXAMINATIONS SECONDARY FOUR COMPUTING 7155/01 Paper 1 Written 24 Aug 2018 2 hours Candidates answer on the Question Paper No Additional Materials are required. Mark Scheme For Examiner’s Use This document consists of 10 printed pages. 80

2 1 (a) Convert the denary number 4351 into a hexadecimal number. Show your working. Denary Quotient Remainder 4351 271 15 271 16 15 16 1 0 1 0 1 The hexadecimal equivalent of 4351 is 10FF. [2] (b) Convert the binary number 11010101 into a denary number. Show your working. 128 64 32 16 8 4 2 1 27 26 25 24 23 22 21 20 1 1 0 1 0 1 0 1 128+64+16+4+1 = 213 The denary equivalent of 11010101 is 213. [2] (c) Describe two common uses of the hexadecimal number system. RGB colour codes – hexadecimal number is used to express the intensities of red, green and blue light in the form of #RRGGBB this allows HTML and CSS users to change site colours to required colours based on the number keyed in. Memory Dump – hexadecimal number system is deal for displaying every byte in memory used by the program in a compact manner. Allowing experience programmers to interpret and work out the cause of program failure. Network Addresses – hexadecimal numbers are used to express the unique internet protocol address in a more compact way. It is also used to express computer Media Access Control (MAC) address which identify each hardware device uniquely. ASCII and Unicode – Hexadecimal number is used to express different characters in languages other than English as a standard that can be used all over the world. URL Encoding – Hexadecimal number is used in Uniform Resource Locator (URL) to represent reserved characters that is part of a web address. [4]

3 2. Insert six of the following words about types of software licences in the correct places in the text below. Most commercial software are under legal protection and copyright, and they are also known as proprietary software. Unauthorised copying is illegal and majority of the source code is kept secret. Only after these legal protection have expired, been surrendered or are simply inapplicable would these programs become public domain software. A type of software known as freeware is similar to proprietary software except that it is available for use at no cost. It usually allows users to try a limited version of the software. While shareware is usually the demonstration software that is distributed for free for a specific evaluation period. [6] 3 Computer networks are common nowadays. Most homes are equipped with a simple modem and a router to link the mobile devices at home to the same network. Identify two other network devices. In each case, explain the function of the device. Network Interface Card (NIC) Pro