Chapter 16: Machines & Computational Models

Question 1

Main features of Von Neumann Architecture

Answer 1

• Data & instruction both stored as binary digits together in the same RAM
• Instructions fetched from memory serially
• The processor decodes & executes an instruction before fetching the next instruction
• The cycle continues until no more instructions are available

Question 2

PC

Answer 2

Holds the memory address of the next instruction to be fetched. Increments by 1 as the FDE cycle runs

Question 3

MAR

Answer 3

Contains the memory address of either the next instruction to be fetched or the address of where the results of the current process are to be stored

Question 4

MDR

Answer 4

Holds the contents found at the address held in the MAR, or data which is to be transferred to main memory

Question 5

IX

Answer 5

Register used when performing operations involving index addressing

Question 6

Multi-core processors

Answer 6

Can work together on the same program (parallel processing) or they can work together on multiple programs (multitasking)

Question 7

Parallel processing

Answer 7

Multiple tasks are completed at the same time by different processors

Question 8

Serial processing

Answer 8

One task at a time is completed by one processor

Question 9

Multiple cores

Answer 9

Having multiple cores means that a computer can potentially accomplish more tasks in a given amount of time

Question 10

Virtual memory

Answer 10

Area of the hard disc drive that is used as temporary RAM when the actual RAM is full. It is the use of secondary storage as additional primary memory

Question 11

When is virtual memory used?

Answer 11

Used when the amount of RAM needed to hold all running programs & data is greater than the amount of RAM available to the computer

Question 12

How virtual memory works

Answer 12

• OS uses part of secondary storage to act as part of main memory (1)
• OS moves programs that are not immediately needed out of main memory (1) & stores them in virtual memory (1) using paging (1)
• Active programs are swapped into main memory from virtual memory (1)

Question 13

SRAM

Answer 13

Type of RAM that retains data bits in its memory as long as power is being supplied & doesn’t need to be constantly refreshed

Question 14

SRAM features

Answer 14

• Cache uses SRAM
• Uses flips flops to hold each bit of memory
• Doesn’t need to be constantly refreshed

Question 15

Algorithm

Answer 15

A precise method for solving a problem, consisting of a sequence of step- by- step instructions

Question 16

Input

Answer 16

The process of entering data into a computer/ The information entered into a computer system

Question 17

Output

Answer 17

The process of displaying data that has been processed or stored/ The information that a device displays

Question 18

Process

Answer 18

Performing a series of actions on the inputs according to a given set of rules

Question 19

Computational models

Answer 19

Describe how algorithms are executed by a machine

Question 20

Sequential

Answer 20

Following instructions in an algorithm step by step in a specific order, one after the other, from start to finish

Question 21

Parallel

Answer 21

Processes are distributed between 2 or more processors. Each separate part of the algorithm that each processor processes can be combined together

Question 22

Multi- Agent

Answer 22

Separate tasks/ algorithms are processed by different systems to perform a particular function. Each agent is autonomous & acts independently and under its own control