CWSS 2020 Computing P1

1 COMMONWEALTH SECONDARY SCHOOL PRELIMINARY EXAMINATION 2020 COMPUTING Paper 1 (Theory) Name: _____________________________________ ( ) Class: ___________ SECONDARY FOUR EXPRESS/NORMAL ACADEMIC Wednesday 2nd September 2020 7155 / 01 0800 – 1000 2 h READ THESE INSTRUCTIONS FIRST Candidates answer on the Question Paper. No Additional Materials are required. Answer all questions. 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. 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. Name of setter: Mrs Leong Sai Hong For Examiner’s Use Parent’s / Guardian’s Signature: _____________________ / 80 This paper consists of 12 printed pages including the cover page. [Turn over]

2 1 The table below contains statements about types of memory or storage. Tick (✔) one or more boxes in each row to indicate if the statement is about register, main memory or secondary storage. Statement Register Main Memory Secondary Storage Data is lost during power interruption Non-volatile memory Slowest accessing speed Storage space directly used by the arithmetic logic unit and the control unit Used to transfer large amounts of data from one device to another [5] 2 Match each of the following types of licences to its description. Licence Description Free and Open Source • • Software that is free for use for a period after which users will need to pay a fee to continue to use it. Public Domain • • Software where unauthorised copying of it is prohibited and its source code is kept secret. Freeware • • Software that is available as “lite” version where users may use at no cost. Shareware • • Software that is available for users to use, copy, study and modify. Proprietary • • For intellectual property that have expired or simply surrendered. [5]

3 3 (a) Convert the (i) denary number 89 into a 8-bit binary number. ________________________________________________________ ________________________________________________________ [1] (ii) hexadecimal number 9B into a denary number. ________________________________________________________ ________________________________________________________ [1] (iii) binary number 11100101 into a hexadecimal number. ________________________________________________________ ________________________________________________________ [1] (b) (i) ASCII and Unicode are two applications of the hexadecimal number system. Explain why Unicode is a preferred choice over the ASCII standard for character encoding. ________________________________________________________ __________________________________