Advanced level 2025 North West regional mock computer science 2
Advanced level 2025 North West regional mock computer science 2
L (a ) ((ii i)).. Briefly Explainexplain why the the use term of arun compiler –time error rather . than an .m c elcr –an <2 mark*)
errors.
(iii). Define the following:
– Handshaking in relation to device communication
– syntax in relation to programming languages
– semantics in relation to programming languages
| (2,2,2,2 marks) | – interrupt in relation to processes scheduling |
| t | . . |
| (b) Real numbers are stored in a certain computer using two by tes%h are divided into a sign bit, 10 bits for | |
| ‘* complements |
|
| mantissa; and 6 hits for exponent. The exponent is also *e | * I he representation is ason |
the figure below:
PHI cun
sign — i i mantissa i r i i i ‘:ri sign
| bit | bit (i) Represent the number 64.25m in this computer ( ii) If the two bytes in the computer contain the hexadecimal number |
(2 marks) rolculale the decimal equivalent of |
J exponent
1 this number. 12 marks)
(iii) Outline the representation of the largest positive numbci in this conipu cr. (I mark)
2. (a) (i) With the aid of a diagram and using oniy NAND gates, design an OR &alc
(ii) A logic circuit has three inputs A, B and C and one output D.
(2 marks)
R1
c:
| A – |
* |
| When a signal at A is “0” then the output at D is the same as input signal B; when a signs!at A is 1 ’hen t e output at |
|
| D is the same as input signal at C. – Construct the truth table for this circuit. – From the results of the truth table, construct a Boolean expression for the output D. – Simplify the expression for D. – Draw the logic circuit that corresponds to your answer for the simplified D. |
(4 marks) (2 m2rks> (2 marks) (2 marks) |
(b) A sensor is a micro device that detects and measures physical or environmental parameters, such as temperature,
pressure, light, motion., sound etc.
(i) Describe two areas of sensors application
(ii) Explain why the signal from a sensor requires conversion before processing in a computer, f 1 mark)
(c) What is the main difference between Cloud computing and Internet of Things?
(2 marks)
< 2 marks *
3. (a) (i) Describe the function of an interrupt register.
(ii) Explain how the processor which is currently servicing one interrupt could deal with smother interrupt (2. marks)
(2 marks)
(iii) Outline one application/use of:
– stack data structure
– queue data structure
(h) (i) Define recursion.
(ii) Explain one advantage and one disadvantage of using recursions in programming.
The following algorithms have been written as part of a large statistical package,
function FACT(val N integer) result integer
if N– 2 then
(2 marks)
(2 marks)
(2 marks)
return N
else
return N * FACT(N – 1)
endif
endfunction FACT
function PFRM(val n integer, val r integer) result integer
PERM <-FACT(n) / (FACT(r)*FACT(n – r»
endfunction
(iii) Using a trace table , or otherwise, determine the value of FACT(5).
TKOant osrA#7*s ri MOCK:O:S
(3 marks
