4.6

Question 1

What is hardware?

Answer 1

The physical components of a computer.

Question 2

What is software?

Answer 2

Sequences of instructions that operate over the hardware.

Question 3

What are the two classifications of software?

Answer 3

System software and application software.

Question 4

What is system software?

Answer 4

Software that is responsible for the operating of the computer itself. It enables users to use a computer without having to understand its internal software.

Question 5

What is application software?

Answer 5

Software that solves problems for the user. They support user oriented tasks and do interfere directly with the hardware.

Question 6

What is the need for system software?

Answer 6

Without it a computer would be unable to use application software.

Question 7

What are the three different types of application software?

Answer 7

General purpose, special purpose and bespoke.

Question 8

What is general purpose application software?

Answer 8

Software that is appropriate for a wide range of uses.

Question 9

What is special purpose application software?

Answer 9

Software that is created for a specific application. It is created for a specific customers.

Question 10

What is bespoke application software?

Answer 10

When software must be written from scratch to solve a particular task.

Question 11

What types of system software are there?

Answer 11

Operating systems, Utility programs, Library programs and translators.

Question 12

What is an operating system?

Answer 12

A program that controls the entire operation of a computer and interacts directly with the hardware.

Question 13

What are utility programs?

Answer 13

A systems program designed to perform a common task. This includes formatting and partitioning a disk and virus checkers.

Question 14

What are library programs?

Answer 14

A collection of subroutines that can be used by other programs that link to the libraries.

Question 15

What are the three types of translator?

Answer 15

Compilers assembles and interpreters.

Question 16

What is a compiler?

Answer 16

A program that translates high level code into machine code.

Question 17

What is an assembler?

Answer 17

A translator that translates assembly code into machine code.

Question 18

What is an interpreter?

Answer 18

Translates and executes a high level program one statement at a time.

Question 19

What is the role of an operating system?

Answer 19

To hide the complexities of the hardware and to manage the hardware resources.

Question 20

What are the classifications of programming languages?

Answer 20

High level languages and low level languages.

Question 21

What are the two types of low level languages?

Answer 21

Machine code and assembly language

Question 22

What are the classifications of high level languages?

Answer 22

Imperative and declarative

Question 23

What are imperative high level languages?

Answer 23

They are made up of procedural and object oriented program. They are programs that give commands.

Question 24

What are the advantages of coding in assembly code over high level languages?

Answer 24

• It has a one to one relationship with machine code.
• Can be very precise locally optimised code.
• Directly accesses system level features without having to go via a software interface improving efficiency
• Complete control

Question 25

What are the disadvantages of assembly code over high level languages?

Answer 25

- Machine dependent (device specific) - Very few skilled programmers - Long and tedious to write in - Difficult to understand modify and maintain.

Question 26

What is an important feature of imperative languages?

Answer 26

They can change a programs state.

Question 27

How does an assembler work?

Answer 27

Assembly language has a one to one correspondence with machine code. Therefore each line in assembly code is mapped line by line to its machine code equivalent.

Question 28

What does a compiler do broadly? (Specifics later)

Answer 28

A compiler reads a program’s source code and translates it into another language called the object code. It also reports errors in the code.

Question 29

What can object code include?

Answer 29

- Machine code - Intermediate code that can be interpreted by an interpreter eg java bytecode - Executable code for inside a virtual machine

Question 30

Does a compiler execute code?

Answer 30

No it only translates it.

Question 31

What are the stages of compilation?

Answer 31

Lexical analysis, syntax analysis, semantic analysis, intermediate code generation, code optimisation and code generation.

Question 32

What is lexical analysis in the context of a compiler?

Answer 32

It is when the source code is split up into language defined words eg “while”.

Question 33

What is syntax analysis in the context of a compiler?

Answer 33

Checks that statements are grammatically correct.

Question 34

What is semantic analysis in the context of a compiler?

Answer 34

Checking for type errors.

Question 35

What does an interpreter do?

Answer 35

An interpreter executes a high level program statement by statement. It does this by recognising what type of statement a given statement is eg a variable declaration. It the calls a prewritten function that executes the statement.

Question 36

What are the differences between a compiler and an interpreter?

Answer 36

- An interpreter translates and executes while a compiler only translates - A compiler produces an independent form of the source code while an interpreter does not. - The interpreter has to be on the machine that is running the code whereas a compiler doesn’t have to occur on the same computer that is running it. - Compilers are not as good at pinpointing errors.

Question 37

When are assemblers a good choice of translator?

Answer 37

For time critical sections of code as assembly code can be highly optimised. It is also used where direct access to the hardware is required.

Question 38

When are compilers a good choice of translator?

Answer 38

When the program is distributed it hides the source code. This is useful commercially or whenever someone wants to hide their source code. Compiled code is also faster.

Question 39

When are interpreters a good choice of translator?

Answer 39

During development as they can locate errors easily.

Question 40

What is bytecode?

Answer 40

An intermediate language between machine code and high level language code. It comes from a compiler.

Question 41

How is bytecode used?

Answer 41

It runs on a pretend virtual machine which converts it into machine code.

Question 42

What logical gates do you need to know for the exam?

Answer 42

Or, nor, and, nand, XOR, not

Question 43

Can you recognise a full adder and a half adder?

Answer 43

If not google it.

Question 44

Can you draw a half adder?

Answer 44

If not google it.

Question 45

What is an edge triggered D-type flip flop?

Answer 45

A RAM memory unit. It can only change its value when the clock is on a rising edge (if a positive flip flop) or a falling edge (if a negative flip flop).

Question 46

What is a flip flop?

Answer 46

A basic circuit that can store one bit and flip it between 0 and 1

Question 47

What are the inputs for a flip flop?

Answer 47

A control input (often labelled as D) and a clock signal.