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COA511S - COMPUTER ORGANISATION AND ARCHITECTURE - 2ND - JAN 2025 |
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n Am I BI A u n IVER s I TY
OF SCIEnCE Ano TECHnOLOGY
FACULTYOF COMPUTING AND INFORMATICS
DEPARTMENTOF COMPUTERSCIENCE
QUALIFICATION:BACHELOROF COMPUTERSCIENCE,BACHELOROF COMPUTERIN CYBER
SECURITY& BACHELOROF INFORMATICS
QUALIFICATIONCODE: 07BACS, 07BCCS&
07BAIF
LEVEL:5
COURSE:COMPUTERORGANISATION
AND ARCHITECTURE
COURSECODE:COASllS
DATE: JANUARY2025
PAPER:THEORY
DURATION: 2 HOURS
MARKS: 100
SECONDOPPORTUNITY/SUPPLEMENTARYEXAMINATION QUESTION PAPER
'
EXAMINER(S) MR. JULIUS SILAA
MR. PHIUSSHAMBABI
MR. ERICl<YIIPUMBU
MR. ANDREASAMUl<WA
MS. JENNYPHARl(AVll<AIRUA
MS. HILLARYl<WALA
MR. ADRIAAN GOBLER
MODERATOR: MR. SEBASTIANMUl<UMBIRA
THIS QUESTION PAPERCONSISTSOF 5 PAGES
(Excluding this front page)
INSTRUCTIONS
1. Answer ALL the questions on the answer scripts.
2. Write clearly and neatly.
3. Number the answers clearly.
PERMISSIBLEMATERIALS
1. Calculator.
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SECTION A [15 MARKS]: Each Question Weighs 1 Mark.
Indicate whether each of the following statements is True or False.
1. A microprocessor's speed is maximized when it receives a continuous stream of
instructions without any interruptions. [True/False]
2. In a pipelined processor, multiple instructions can be executed at the same time, each in
different stages of completion. [True/False]
3. The simplified instruction set of RISCprocessors allows for faster interrupt handling
compared to CISCprocessors. [True/False]
4. Machine parallelism refers to the simultaneous execution of independent instructions,
which can enhance overall performance. [True/False]
5. Organizational attributes, such as the hardware design of a computer, are typically
hidden from the programmer and do not affect how the programmer writes code.
[True/False]
6. The Instruction Set Architecture (ISA)defines the set of instructions a processor can
execute and determines how software interacts with hardware. [True/False]
7. Cache memory is generally faster than the register file because it is closer to the
processor core. [True/False]
8. Overflow in arithmetic operations can occur without a carry, depending on the type of
operation and how data is represented. [True/False]
9. The typical states of a process include: new, ready, running, waiting, and terminated,
while interrupt handling is a separate mechanism. [True/False]
10. Memory swapping occurs when a process is moved to secondary storage to free up main
memory for other processes. [True/False]
11. A hexadecimal digit represents 4 bits, and sequences of hexadecimal digits are often
used to represent binary numbers in a more compact form. [True/False]
12. The instruction set of a processor allows the programmer to directly control the
operations the processor performs. [True/False]
13. Memory references are typically faster than register references because memory can
store more data than registers. [True/False]
14. The kernel is the core of the operating system, and it is typically written in low-level
programming languages like C or assembly. [True/False]
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15. A processor's clock frequency, measured in Hertz (Hz), directly affects how many
instructions it can execute per second, influencing its performance. [True/False]
SECTION B [15 MARl(S): Each Question Weighs 1 Mark.
Choose the correct answer for each of the following:
1. Binary 11001010 is hexadecimal ___ _
A. CA
B. 9 A
C. D 2
D. 6 A
2. A ____
can store data indefinitely until an input changes its state.
A. flip-flop
B. decoder
C. multiplexer
D. latch
3. The operand ____
yields true only if both of its operands are true.
A.NOT
B.AND
C. XOR
D. OR
4. A ____
is a part of a process that can execute independently and can have its own
execution context.
A. process
B. thread
C. task
D. process manager
5. In modern ARM architecture, the standard instruction size is ____
bits long.
A. 8
B. 16
C. 32
D.64
6. The ____
is responsible for fetching instructions and decoding them in the CPU.
A. registers
B. control unit
C.ALU
D. system bus
7. In digital circuits, ____
are used to select one out of multiple inputs based on a
selection signal.
A. multiplexers
B. counters
C. flip-flops
D. encoders
8. The ____
identifies the location of the operand.
A. opcode
B. address register
C. source operand
D. data register
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9. The operand ____
can yield true if at least one of its operands is true.
A.AND
B.OR
C. XOR
D. NOT
10. A ____
architecture is designed to use multiple instruction pipelines for parallel
processing of instructions.
A. superscalar
B. scalar
C. hybrid
D. super-pipelined
11. The ____
holds the next instruction to be executed in a sequence.
A. instruction buffer
B. memory address register
C. memory buffer register
D. program counter
12. In floating-point arithmetic, when the exponent falls below the minimum possible
exponent, it is called ____
_
A. significand underflow
B. exponent underflow
C. significand overflow
D. exponent overflow
13. ____
registers are specialized for holding addresses used in memory operations.
A. general purpose
B. address
C. status
D. Control
14. In an optical CD, the areas that store data in the form of pits are called ___ _
A. lands
B. zones
C. sectors
D. tracks
15. The ____
manages the execution of instructions by directing data and control
signals throughout the system.
A. control unit
B. CPU interconnect
C.ALU
D. data path
SECTION C (70 MARKS]: Comprehension questions.
Question 1
(15 Marks]
A new model of Raspberry Pi Phone has 32GB of RAM. The memory in this device is divided
into several words, each consisting of 2048 bytes.
a) How many bits are needed to address any single word in this memory?
Show your work step by step.
(9 marks)
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b) CPUis a vital computer resource and any good computing system should be design in
such way to utilise CPUefficiently. Contrast programmed 1/0 from 1/0 channel.
Why the CPU usage by 1/0 channel CPU is more efficient than Programmed 1/0?
(6 marks)
Question 2
a) Explain your understanding of the following virtual memory concepts
i)
swapping
ii)
demand paging
[08 Marks]
(4 marks)
b) What is the ultimate importance of virtual memory management scheme? (4 marks)
Question 3
[14 Marks]
The following diagram represents a logical circuit. Please provide answers to the
accompanying questions based on your understanding of circuit analysis
a) Provide the name of this circuit
(2 marks)
b) Within the architecture of a CPU,where exactly would you find this circuit? (2 marks)
c) Citing its components A, B, Sand C, describe how this circuit work
(4 marks)
A-----
9..,.___ ----4!----+1
d) Let's say you want to design a circuit that turns on a light (output F)when the two
switch inputs A and B are applied.
Truth Table
A
B
F
0
0
1
0
1
0
1
0
0
1
1
1
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i. Provide a canonical Boolean function (F) for the circuit above
(2 marks)
ii. Suppose this Function does not require any further minimization. Create a visual
representation(circuit) of this Boolean function using logic gates
(4 marks)
Question 4
[10 Marks]
a) Instructions need specific information to execute. Identify four places within a
computer where the data used by an instruction (operands) can be located (4 marks)
b) Provide an example of a low-level computer instruction and briefly describe what
this instruction must specify.
(6 marks)
Question 5
[12 Marks]
Addressing modes specify how an instruction finds its operand. Explain this with
examples of:
a) Implicit addressing mode
(3 marks)
b) Register Indirect addressing mode
(3 marks)
c) Relative addressing mode
(6 marks)
Question 6
[11 Marks]
a) Imagine opening Facebook on your phone. Behind the scenes, your phone's CPUfollows
a series of steps to make this happen. Explain the six stages the CPU goes through to
process the instructions that allow you to use the app.
(6 marks)
b) The Program Status Word (PSW) holds key information about a program's current state.
Name and briefly explain five common status flags found within a PSW. (5 marks)
*****END OF PAPER*****
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