2.2 Fundamentals of computer systems

Question 1

Define hardware

Answer 1

A generic term for the physical parts of the computer, both internal and external

Question 2

Define software

Answer 2

A generic term for any program that can be run on a computer

Question 3

Define application software

Answer 3

Programs that perform specific tasks

Question 4

Define system software

Answer 4

The range of programs that are concerned with the setup and running of the computer - the 4 main types of system software are utility programs, library programs, translators, and operating system software

Question 5

Define utility program

Answer 5

Programs that perform specific common tasks relating to the running of the computer

Question 6

Define library program

Answer 6

Code, data, and resources that can be called by other programs

Question 7

What is a translator?

Answer 7

Software that converts programming language instructions into machine code. There are 3 types of translator - compilers, assemblers, and interpreters

Question 8

What is a compiler?

Answer 8

A program that translates high-level language into machine code by translating all of the code in one block. This will often create a file such as a .exe file which will not need translating to be run again

Question 9

What is an assembler?

Answer 9

A program that translates a program written in assembly language to machine code

Question 10

What is an interpreter?

Answer 10

A program for translating a high-level language into machine code by reading each statement in the source code line by line and performing the action. Code that is translated by an interpreter will need to be interpreted each time it is run

Question 11

Define operating system software

Answer 11

A suite of programs designed to control the operations of the computer

Question 12

Define virtual machine

Answer 12

The concept that all of the complexities of using a computer are hidden from the user and other software by the operating system

Question 13

What tasks are performed by the operating system?

Answer 13

• Controls start-up configuration of the computer
• Recognises input from peripherals and decides what action to take
• Sends signals to hard disk controller telling it what programs to transfer to memory
• Decides what sections of memory to allocate to the program currently running
• Attempts to handle errors
• Ensure complete and correct shutdown process
• Controls print queues
• Manages users on a network

Question 14

Define resource management

Answer 14

How an operating system manages hardware and software to optimise the performance of a computer. This includes tasks such as managing input/output devices, memory management, file management, and scheduling tasks

Question 15

Define scheduling

Answer 15

A technique to ensure that different users or different programs are able to work on the same computer system at the same time

Question 16

Define memory management

Answer 16

How the operating system uses RAM to optimise the performance of the computer

Question 17

Define file management

Answer 17

How an operating system stores and retrieves files

Question 18

Define machine code

Answer 18

The lowest level of code that is completely understandable by a computer, which is written in binary

Question 19

Define assembly language

Answer 19

A way of programming that involves writing mnemonics. This is one level above machine code

Question 20

Why is assembly language used?

Answer 20

• Programs are executed quickly as a compiler does not optimise the machine code it produces as effectively as a programmer writing assembly language
• Program code is relatively compact
• Assembly language allows for direct usage of registers on the processor, giving lots of control over how the program is run

Question 21

Define source code

Answer 21

Programming code that has not yet been compiled into an executable file

Question 22

Define object code

Answer 22

Compiled code that can be run as an executable on any computer

Question 23

Define low level language

Answer 23

A programming language that is machine oriented, this refers to assembly language and machine code

Question 24

Define high level language and what are the 4 main types?

Answer 24

A programming language that allows programs to be written using English keywords and that is platform independent. The 4 main subsections of this are imperative, object-oriented, declarative, and functional (a subset of declarative)

Question 25

What are the characteristics of a high level language?

Answer 25

• It is easier for a programmer to recognise what a command word does
• Require translation
• One to many relationship between lines of high level language code and lines of machine code
• Portable
• Make use of a wide variety of program structures that make writing in them more straightforward, which also makes them easier to maintain

Question 26

Define imperative language

Answer 26

A language based on giving the computer commands or procedures to follow

Question 27

Define object-oriented language

Answer 27

A programming paradigm that encapsulates instructions and data together into objects

Question 28

Define declarative language

Answer 28

Languages that declare or specify what properties a result should have e.g. results will be based on functions

Question 29

Define functional language

Answer 29

A programming paradigm that uses mathematical functions

Question 30

What is a translator?

Answer 30

The general name for any program that translates code from one language to another, for example translating source code to machine code

Question 31

Define interpreter

Answer 31

A program for translating a high level language by reading each statement in the source code and immediately performing the action

Question 32

Define compiler

Answer 32

A program that translates a high level language into machine code by translating all of the machine code

Question 33

What are the pros and cons of using an interpreter?

Answer 33

Pros:
- You do not need to compile the whole program in order to run small sections of code, as it can be executed one statement at a time
- As the code is translated each time it is executed, it can be run on processors with different instruction sets
Cons:
- Each line of code will need translating again each time it is executed, meaning the time taken to execute a problem can be long
- The source code can only be translated and executed on a computer that has the same interpreter installed
- The source code must be distributed to users

Question 34

What are the pros and cons of using a compiler?

Answer 34

Pros:
- Once the source code has been compiled, you no longer need the compiler or the source code
Cons:
- The object code will only work on a computer that has the same platform
- As the whole program must be converted from source code each time, it can take longer to debug

Question 35

Define bytecode

Answer 35

An instruction set used for programming that can be executed on any computer using a virtual machine

Question 36

Define boolean expression

Answer 36

An equation made up of Boolean operations

Question 37

Define logic gate

Answer 37

An electronic component used to perform Boolean algorithms. A logic circuit is defined as a combination of logic gates

Question 38

Define half adder

Answer 38

A circuit that performs addition using inputs from A and B only

Question 39

Define full adder

Answer 39

A circuit that performs addition using inputs from A and B plus a carry bit

Question 40

Define carry bit

Answer 40

Used to store a 0 or 1 depending on the result of binary addition

Question 41

What is a flip flop?

Answer 41

A memory unit that can store 1 bit

Question 42

What is an edge triggered D type flip flop?

Answer 42

A memory unit that changes state with each pulse of the clock