1. Computer Development

Question 1

What are the four main subcategories of computational devices?

Answer 1

PCs, servers, supercomputers and embedded computers.

Question 2

What is Moore’s Law?

Answer 2

Moore’s law states that the number of transistors per microchip doubles every two years.

Question 3

What is the difference between a gibibyte and a gigabyte?

Answer 3

A gibibyte is 1024 mebibytes and a gigabyte is 1000 megabytes.

Question 4

What is a PMD?

Answer 4

Personal Mobile Device: a small wireless device that connects to the Internet. They are battery-powered and software is installed by downloading apps.

Question 5

How does Moore’s law affect design of technology?

Answer 5

Designers must design in accordance with how advanced technologies will be when they finish the project.

Question 6

What is abstraction in computer design?

Answer 6

Hiding away details from the user to make interfaces simpler.

Question 7

Why should designers spend time optimising the common case, but not necessarily the rare case?

Answer 7

The rare case is often much harder to optimise than the common case.

Question 8

What is parallelism?

Answer 8

The multiple instances of a certain program.

Question 9

What is pipelining?

Answer 9

The ‘staggering’ of parts of a process, so that different processor parts can be running in parallel.

Question 10

What is performance via prediction?

Answer 10

Where computations are carried out before knowing if they will be required.

Question 11

What is a hierarchy of memories?

Answer 11

The smallest memory is placed in the primary spot, and then subsequent memories in order of size. The smallest memory should be the fastest to access, and they get slower as the memory size increases.

Question 12

What is dependability via redundancy?

Answer 12

We make systems dependable by including components that take over when systems fail or to help to detect failures.

Question 13

Give three roles of the Operating System (OS).

Answer 13

Handling basic input and output operations.

Allocating storage and memory.

Providing for protected sharing of the computer among multiple applications using it simultaneously.

Question 14

What is the function of the assembler?

Answer 14

To convert programs to binary instructions.

Question 15

What are the three main benefits of high-level languages?

Answer 15

1. The programmer can think in a more natural language; using English words and algebraic notation. This means more specific languages can be developed.
2. Much quicker to develop programs written concisely.
3. The programs are independent of the computer on which they were written.

Question 16

What are the five classic components of a computer?

Answer 16

Input, output, memory, datapath and control.

Question 17

What is an ISA?

Answer 17

The list of instructions a processor can perform, as well as the I/O devices present. It means that many implementations of varying cost and performance can run the same software.

Question 18

Classify main / primary memory and secondary memory as volatile or non-volatile.

Answer 18

Main memory / primary memory are volatile and secondary is non-volatile.

Question 19

Compare DRAM and SRAM.

Answer 19

DRAM and SRAM are: non-volatile, and have a smallest write of a byte. They also require high power.

DRAM is cheaper than SRAM, but is not quite as fast at reading/writing, and has a smallest read of a page (instead of a byte). DRAM also needs regular refreshing.

Question 20

Define response/execution time.

Answer 20

The total time required for the computer to complete a task, including all memory accesses, I/O activities and CPU time

Question 21

Define throughput/bandwidth.

Answer 21

The number of tasks per unit time.

Question 22

Computer X takes 1ns to compute a sum. Computer Y takes 4 times this. What is the performance of Computer Y?

Answer 22

0.25 s^-1

Question 23

Compare CPU time, user CPU time and system CPU time.

Answer 23

• CPU time is the total time spent in a task.
• user CPU time is the time spent in a program itself.
• system CPU time is the time spent in the OS performing tasks for the program.

Question 24

State the relationship between clock rate and clock period.

Answer 24

clock rate = 1/(clock period)

Question 25

(CPU clock cycles for a program)/(Clock rate) = ?

Answer 25

CPU execution time

Question 26

Instructions for a program x CPI = ?

Answer 26

CPU clock cycles for a program.

Question 27

Time = Instructions/? x Clock cycles/? x Seconds/?

Answer 27

Instructions/Program x Clock cycles/Instruction x Seconds/Clock cycle

Question 28

Why is execution time the only valid and unimpeachable measure of performance?

Answer 28

No other metric covers all the factors affecting performance.