Advanced level 2025 Holy Infant High School mock Computer science 2
Advanced level 2025 Holy Infant High School mock Computer science 2
The following is a floating-point representation of a number:
a) Calculate the decimal equivalent of the number. (2 marks)
b) Write the normalized floating-point representation of the decimal number 58.5. (3 marks)
(ii) Identities are often applied to help simplify Boolean expressions. One such identify is:
𝐴. 𝐴̅ = 0
a) Without using a truth table, explain why this identity is true. (2 marks)
b) Using the rules of Boolean algebra, simplify the following Boolean expression: (3 marks)
𝐵 ̅ ̅̅̅̅̅̅.̅̅𝐴̅̅̅.̅𝐵̅̅ + 𝐴. 𝐵
(iii)
a) Describe the stored program concept in von Neumann Machine architecture. (3 marks)
b) Illustrate with registers how an instruction is fetched and loaded for execution (4 marks)
2)
(i) Jay is developing a computer game that allows users to create stories.
| a) | Jay uses a language translator to develop the computer game. Tick (√) one or more boxes in each row to identify the language translator(s) each statement describes. |
| Statement | Assembler | Interpreter | Compiler |
| Translates and executes each line of source code one line at a time |
|||
| Translates low-level source code into machine code |
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| Must be present in memory to execute the code |
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| Translates high-level source code into low-level code |
(4 marks)
b) Jay decides to use a compiler to develop the game. Identify two benefits of using a compiler.
(2 marks)
(ii) A set of photographs has been taken for a wedding. All the guests are to be sent digitally stored copies through
the ordinary postal service. There are fifty photographs and each photograph is between 1.8 and 2.5 megabytes
in size.
a) Work out the maximum storage space required for a set of photographs. State, with a reason, a suitable
medium to use for the copies to be sent to the guests. (3 marks)
b) Explain what is meant by primary, secondary and off-line storage. Give an example of each.
(3 marks)
(iii) A computer uses a memory unit of 512K words of 32 bits each. A binary instruction code is stored in one word
of the memory. The instruction has four parts: an addressing mode field to specify one of the two-addressing
mode (direct and indirect), an operation code, a register code part to specify one of the 256 registers and an
address part.
a) How many bits are there in addressing mode part (1 mark)
b) How many bits are there in the register code (1 mark)
c) How many bits are there in the address part (2 marks)
d) How many bits are there in the opcode (2 marks)
