ITC544 | MARIE and ISA | Computer Organisation And Architecture


Question 1

Suppose a disk drive has the following characteristics:  (7 marks)
• 23 surfaces
• 512 tracks per surface
• 64 sectors per track
• 32 bytes/sector
• Track-to-track seek time of 10 milliseconds
• Rotational speed of 9600 RPM

  1. What is the capacity of the drive?
    II. What is the rotation delay?
    III. What is the access time?

Question 2

A digital computer has a memory unit with 32 bits per word. The instruction set consists of 232 different operations. All instructions have an operation code part (opcode) and an address part (allowing for only one address). Each instruction is stored in one word of memory.  (8 marks)

  1. How many bits are needed for the opcode?
    II. How many bits are needed to specify the register?
    III. How many bits are left for the address part of the instruction?
    IV. What is the maximum allowable size for memory?
    V. What is the largest unsigned binary number that can be accommodated in one word of memory?

Question 3

In a computer instruction format, the instruction length is 13 bits and the size of an address field is 5 bits. The system architect has already designed FIVE 2-address instructions and TWENTY 1-address instructions. How many 0-address instruction still possible to accommodate for the instruction set architecture?  (6 marks)

Question 4

Write code to implement the below expression:  (9 marks)

A = (X+Y) * (Y-Z) / (X * Y) on 2, 1 and 0 address machines.



This assessment task covers topics on CPU operation and Instruction Set Architecture, and has been designed to ensure that you are engaging with the subject content on a regular basis. More specifically it seeks to assess your ability to:

  • be able to investigate the internal operation of the Central Processing Unit (CPU) and describe how it is used to execute instructions;
  • be able to investigate and describe in detail the essential elements of computer organisation including internal bus, memory, Input/Output ( I/O) organisations and interfacing standards and discuss how these elements function;

Marking criteria


HD (85%-100%)

DI (75%-84%)

CR (65%-74%)

PS (50%-64%)

FL (0%-49%)

Simulating and investigating of internal operations of CPU and it's instruction execution

The code meets the specification. Code is well documented with comments. The program produces correct outputs in every input situations.

 Code meets specification and is well documented with comments. Minor errors in explanations.

Code meets specification. Most of the time produces correct results, however does not produce correct results for special inputs. Little documentation and comments.

Code meets specification but has errors in operation. Little commenting. Basic idea is expressed by the codes and explanations.

Code does not meet the specification

 Comprehension of internal elements of computer organisation

Answers are corrects. All steps are correctly shown.

All codes are accurately written.

All answers are correct with a minor error. All codes are correct except a minor error.

Few minor errors in calculating the address spaces. The steps show the clear understanding of the address space calculation. 

All codes written correctly however the order were not maintained correctly.

The final result is not correct, however the calculations show the basic understanding of the instruction set architecture.

More than half of the codes are correct.

No attempt or incorrect calculations showing no or minimum understanding of the topic.

Codes do not meet the specification.