Unit 4 - Hardware and software

Question 1

What are the two types of software?

Answer 1

The two types of software are system software and application software.

Question 2

What are the four types of system software?

Answer 2

The four types of system software are: operating systems, utility programs, library programs and translators.

Question 3

What are the two types of application software?

Answer 3

The two types of application software are general purpose and special purpose.

Question 4

What is the general purpose of all system software?

Answer 4

System software is required to run and manage the computer’s hardware and application programs (a.k.a the system).

Question 5

List three example purposes of system software.

Answer 5

• Allocating jobs to the processor
• Peripheral management
• Maintaining security and checking for viruses
• Software installation
• Translating program code into machine code.

Question 6

What is the general purpose of the operating system?

Answer 6

The operating system acts as a bridge between the computer’s hardware and the software.

Question 7

Give an example of a task performed by the operating system.

Answer 7

• Resource management (Processor management, memory management, backing store management and IO management)
• Provision of a user interface, such as a GUI or command line

Question 8

What is the general definition of utility software?

Answer 8

Utility software is designed to analyse, configure, optimise, maintain or otherwise aid in the running of a computer system.

Question 9

Give two examples of utility software.

Answer 9

• Virus checkers
• Automatic backup and restore
• Disk defragmentation
• File compression

Question 10

What is the general definition of a library?

Answer 10

A library is a collection of pre-compiled routines that can be used by other programs. An example would be ArrayLists in Java.

Question 11

What is machine code?

Answer 11

Machine code is the lowest level of instruction comprised of pure binary. It is the only level of instruction that computers can process.

Question 12

What is the purpose of a translator?

Answer 12

A translator is used to translate code from assembly language or a high level language down to machine code.

Question 13

What are the three types of translator?

Answer 13

A translator can be: an assembler to translate between assembly and machine code, a compiler to compile a high level language down to executable object/machine code or an interpreter which directly executes the instructions from the high level language.

Question 14

Is a translator an example of a utility program?

Answer 14

Nope.

Question 15

What is the general purpose of application software?

Answer 15

Application software aids in the completion of different tasks. Examples are: word processors, image editors, internet browsers and email clients.

Question 16

What are the four categories of application software?

Answer 16

• General purpose
• Special purpose
• Bespoke
• Off-the-shelf

Question 17

Give two advantages of off-the-shelf software.

Answer 17

• Readily available
• Low cost
• Often well-documented and well-tested

Question 18

Give a disadvantage of off-the-shelf software.

Answer 18

• No control over the included features

- Will often contain additional unnecessary features

Question 19

What is used to hide the complexities of a computer’s operation from the user?

Answer 19

An API (Application Programming Interface)

Question 20

What does an API do?

Answer 20

An API allows the user to issue complex commands in a simple manner, such as by clicking an icon on a desktop.

Question 21

What is the purpose of processor scheduling?

Answer 21

Processor scheduling controls which programs can send data to the processor to be processed. Multiple requests are queued.

Question 22

What the purpose of the scheduler module within the operating system of a computer?

Answer 22

The scheduler manages how processor time is used between programs. Three common algorithms are: round robin, where each process is allocated some time every second, shortest job next and a priority system.

Question 23

What is backing store management?

Answer 23

Backing store management is a process undertaken by the operating system to keep track of where all files are stored on hard disk or external drives and where space is available for data to be written to.

Question 24

What allows the operating system to communicate with I/O devices? (not drivers)

Answer 24

The I/O controller.

Question 25

Give three examples of functions of the operating system.

Answer 25

• Memory management
• Processor scheduling
• Backing store management
• Peripheral management of IO device

Question 26

What are the two components of a machine code instruction?

Answer 26

A typical machine code instruction holds an operation code (opcode) in the first few bits and an operand in the rest.

Question 27

What is the instruction set of a computer and what decides how large it can be?

Answer 27

The instruction set is all the instructions that the computer can understand and execute. The size of the opcode relates to how large the instruction set can be.

Question 28

What is different about assembly language in comparison to machine code?

Answer 28

• The opcode instructions are replaced by mnemonics

- The operand uses decimal or hexadecimal instead of binary.

Question 29

What is the difference between an imperative and declarative high-level languages?

Answer 29

Imperative high-level languages consist of commands for the computer to perform, whilst declarative ones are more focused on doing tasks without going into detail on how they are done.

Question 30

Which level of programming languages is portable?

Answer 30

Only high-level language are portable, meaning a program written for one type of computer can be used on any other computer if recompiled.

Question 31

What is the source code and object code for an assembler?

Answer 31

The source code is the assembly code being input to the assembler. The assembler outputs machine code called object code. Only object code can be executed.

Question 32

What is the source code in programming language translators?

Answer 32

The source code is the code input to the translator, such as high-level code for a compiler/interpreter and assembly code for an assembler.

Question 33

What is the object code in a programming language translator?

Answer 33

The object code is the machine code that is output by the translator.

Question 34

What kind of code is output from a compiler after detecting errors but before it is saved to machine code?

Answer 34

The intermediary code for a compiler is called “relocatable code” as the addresses of the program are not fixed at this point. It becomes machine code when it is saved.

Question 35

Advantages of a compiler instead of an interpreter:

Answer 35

• The object code post-compilation can be distributed and executed without the compiler
• The object code runs faster than interpreted code
• The object code is more secure, as binary is much harder to read and modify compared to the high-level code.

Question 36

Between compilers and interpreters, which outputs object code?

Answer 36

Only compilers output object code.

Question 37

When is an interpreter more useful than a compiler?

Answer 37

An interpreter is more useful when a programmer wants to test a small piece of code but doesn’t want to wait to recompile the whole program.

Question 38

What is bytecode and why is it useful?

Answer 38

Bytecode is an intermediate form and is also portable because every computer that can run Java has a Java Virtual Machine that can convert the bytecode into the correct machine code based on the device.

Question 39

System software definition.

Answer 39

System software is designed to run a computer’s hardware and application programs. It acts as an interface between hardware and user applications. An example would be the operating system.

Question 40

Utility software definition.

Answer 40

Utility software exists to assist the maintenance of a computer. It is not designed to help the user in a way they will notice.