ZHSS 7155_PRELIMS_2022_4E_P1_MS

7155_PRELIMS_2022_4E_P1_Mark_Scheme Question 1 (a) {One mark each} C – Register E – Read Only Memory F – Secondary G – Data H – Address X – Input (b) Control Unit functions: {Any two to score 2 marks}  Follows instructions and decides WHEN data should be stored, received or transmitted by different parts of the computer.  It makes sure that data is transported to WHERE it needs to be.  Makes sure the data is processed in the correct order. (c) 264 / 232 = 264-32 = 232 4,294,967,296 times or 4 billion times {accept both answers. Both answer and working correct to score 2 marks, otherwise zero} Question 2 Inputs: Name of the road Estimated duration Start Time End Time {All four identified for 2 marks, deduct a mark for every omission or mistake} Output: Monetary amount that was deducted {1 mark} Process: Calculate the amount owed using the parking duration referenced against a parking rate table. Deduct the amount from the motorist’s credit card {All two identified for 2 marks, deduct a mark for every omission or mistake}

7155_PRELIMS_2022_4E_P1_Mark_Scheme Question 3 (a) Trace Table Completion: {All 6 columns correct to score 5 marks, deduct a mark for each incorrect column} x y t x odd? x = 0? OUTPUT 3 7 0 Y 2 7 7 N 1 14 7 Y 0 14 21 Y 21 x y t x odd? x = 0? OUTPUT 12 15 0 N N 6 30 0 N N 3 60 0 Y 2 60 60 N 1 120 60 Y 0 120 180 Y 180 (b) The algorithm gives the answer for x multiplied by y. {1 mark} (c) The algorithm uses doubling and halving, to perform multiplication. {1 mark} There is no need to use multiplication tables to perform multiplication. {1 mark}

7155_PRELIMS_2022_4E_P1_Mark_Scheme Question 4 i. It is a data type used to represent text as a sequence of characters or symbols. {both concepts present to award 1 mark} ii. name = ‘Alison’ OR name = “Alison” {no typo allowed} {Award 1 mark for correctly written line} iii. It is the process of converting a value from one data type to another {Award 1 mark for correct definition} iv. It is a data type for storing multiple values in a sequence. {Award 1 mark for correct definition} v. It is where all the items have the same data type / size and are arranged consecutively in memory. {Award 1 mark for correct definition} Question 5 (a) It is a code translator program that translates source code into machine code completely before running the compiled program. {1 mark for complete description} (b) It is a code translator program that translates source code into machine code while the interpreted program is running. {1 mark for complete description} {1 mark per box for complete desription} Compilers Interp