Unit 4 - Hardware and Software

Question 1

What is hardware?

Answer 1

Hardware describes the electrical or electro-mechanical parts of a computer system.

Question 2

What is software?

Answer 2

Software comprises all of the programs that make the computer function.

Question 3

What is system software?

Answer 3

Software that is required to run and manage the computer’s hardware and application programs.

Question 4

What are some forms of system software?

Answer 4

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

Question 5

What is an Operating System?

Answer 5

A form of systems software which handles the communication between the hardware and software.

Question 6

What are some things that operating systems do?

Answer 6

• Memory management,
• Processor scheduling,
• Backing store management,
• Peripheral management of IO devices,
• Provision of a user interface (Command line, Menu driven or GUI)

Question 7

What is utility software?

Answer 7

System software designed to analyse, configure, optimise or maintain a computer system. Some perform additional common tasks needed by most or all users.

Question 8

What are some things that utility software does?

Answer 8

• Disk defragmentation,
• installation and uninstallation of software,
• keeping software up-to-date,
• monitoring resources and performance,
• antivirus software,
• automatically backing up or restoring data,
• file compression.

Question 9

What is a library?

Answer 9

A library is a collection of pre-compiled routines that can be used by other programs.

Question 10

What are translators?

Answer 10

Systems software which translates high and low level code into machine code so that the CPU can run it.

Question 11

What are the three types of translators?

Answer 11

• Assemblers,
• Compilers,
• Interpreters.

Question 12

What is an assembler?

Answer 12

Assemblers translate assembly language into machine code.

Question 13

What is an compiler?

Answer 13

Compilers translate high-level language programs into object code (machine code) which can be saved and run whenever needed, without the compiler having to be present. Different hardware needs to use different compliers because machine code differs from CPU to CPU and so the resulting object code from compilation will not work with every device.

Question 14

How do compliers work?

Answer 14

Compilers go through the source code in multiple phases, each doing something different, such as lexical analysis, syntactic analysis, and semantic analysis, going through the whole program at each stage.
It produces intermediate code, optimises it, then generates the machine code. It will not generate the machine code it there are any errors in the program.

Question 15

What is an interpreter?

Answer 15

An interpreter is a translator which translates high-level instructions into an intermediate form, which it then executes. It produces no object code. Most interpreters scan through source code for syntax errors and will run until they encounter an error or are closed.

Question 16

What is application software?

Answer 16

Application software allows you to complete different tasks.

Question 17

What is general purpose software?

Answer 17

General purpose software is software which can be used for a range of generic tasks. Examples include word processors, graphics programs and spreadsheet software.

Question 18

What is special purpose software?

Answer 18

Special-purpose software performs tasks for a single, specific job. Examples include payroll or accountancy software, media players, calendar programs and online payment systems.

Question 19

What is off-the-shelf software?

Answer 19

Software which is available for everyone to use.

Question 20

What are some advantages of off-the-shelf software?

Answer 20

• The cost is usually lower because development costs are shared among all the buyers,
• It is likely to be well-documented and well-tested.

Question 21

What are some disadvantages of off-the-shelf software?

Answer 21

• You have little or no control over what features there are,
• It may not do exactly what you want.

Question 22

What is bespoke software?

Answer 22

Bespoke software is created to fulfil your own exact specifications.

Question 23

What is an advantage of bespoke software?

Answer 23

Complete control over the process gives you all the functionality you need.

Question 24

What are some disadvantages of bespoke software?

Answer 24

• It can be significantly more costly than off-the-shelf software,
• It may take several weeks, months or even years to develop.

Question 25

What is the scheduler?

Answer 25

The scheduler is the operating system module responsible for ensuring that processor time is used as efficiently as possible.

Question 26

What is an opcode?

Answer 26

The part of a CPU instruction that has an operation code; it tells the CPU what to do. It has 2 parts, the actual command and the addressing mode, which specifies what type of data is in the operand (either a binary value or the address of a register or memory location).

Question 27

What is an operand?

Answer 27

The part of a CPU instruction that has any additional information needed for an action.

Question 28

What is an instruction set?

Answer 28

The instruction set of a computer is all the instructions that it can understand and execute.

Question 29

What is machine code?

Answer 29

A low-level language that is directly understood by the CPU. It is represented by binary numbers and is different for each type of CPU.

Question 30

What is assembly language?

Answer 30

A low-level language which has a one-to-one correspondence with a computer's machine code. It's opcodes are mnemonics and its operands are decimal or hexadecimal values.

Question 31

What is the advantage assembly language has over machine code?

Answer 31

It is much easier to write, understand and debug programs in assembly language.

Question 32

What is the disadvantage assembly language has over machine code?

Answer 32

The assembly code has to be translated into machine code by an assembler.

Question 33

What is a high-level language?

Answer 33

A programming language designed to be human-readable and machine- independent. They typically have strong abstraction from the details of the computer.

Question 34

What are imperative languages?

Answer 34

An imperative language consists of commands for the computer to perform.

Question 35

What is a declarative language?

Answer 35

A declarative language which focuses on what the program should do without listing the steps needed to achieve the result.

Question 36

What is a low-level language?

Answer 36

A programming language designed to be close to machine code whilst being easier to read and write. They typically have very weak or no abstraction from the details of the computer.

Question 37

What are some advantages of high-level languages over low-level languages?

Answer 37

- Much easier and faster to write, debug and maintain programs, - Different high-level languages have been written specifically for different types of problem, - High-level language programs are portable.

Question 38

What are some disadvantages of high-level languages over low-level languages?

Answer 38

- The object code (compiled or interpreted code) may run slower than assembly code or machine code, - The object code may occupy more space in RAM, - Most high-level languages do not have statements to allow the programmer to manipulate individual bits.

Question 39

What is source code?

Answer 39

The code that humans write and read in order to make programs. It cannot be used by a computer unless it is translated.

Question 40

What is object code?

Answer 40

The code that results from the translation of source code into computer-readable format. This is what computers run programs from.

Question 41

What are the advantages of using a compiler?

Answer 41

- Once a program has been compiled, the object code can be distributed and the compiler is not needed to run the program, - The object code runs faster than interpreted code, - The object code is more secure, as machine code cannot easily be read and copied by someone wishing to modify the code and sell it as their own product.

Question 42

What are the advantages of using an interpreter?

Answer 42

- An interpreter is useful in education because it allows students to program interactively using “Interactive mode”, - It is useful during development when a programmer may want to test a small piece of code without recompiling the whole program.

Question 43

What is bytecode?

Answer 43

An intermediate form of compiled code used by some programming languages like Java for increased portability. When it is shared, a specific program that comes with the programming language translates it into the machine code, doing so faster than the time taken to compile the original source code into machine code. Once the bytecode for a particular subroutine or method has been translated into machine code, the machine code is retained for the next time that code is required, so the translation does not have to be done again.

Question 44

What is De Morgan's 1st law?

Answer 44

NOT(A) AND NOT(B) = A NOR B or NOT(A OR B)

Question 45

What is De Morgan's 2nd law?

Answer 45

NOT(A AND B) or A NAND B = NOT(A) OR NOT(B)

Question 46

What are the Boolean logic operators?

Answer 46

. = AND + = OR line over variable = NOT (+) = XOR

Question 47

What are the general rules of Boolean logic?

Answer 47

X AND 0 = 0 X AND 1 = X X AND X = X X AND NOT(X) = 0 X OR 0 = X X OR 1 = 1 X OR X = X X OR NOT(X) = 1 NOT(NOT(X)) = X

Question 48

What is the Commutative rule?

Answer 48

X AND Y = Y AND X X OR Y = Y OR X

Question 49

What is the Associative rule?

Answer 49

X AND (Y AND Z) = (X AND Y) AND Z X OR (Y OR Z) = (X OR Y) OR Z

Question 50

What is the Distributive rule?

Answer 50

X AND (Y OR Z) = X AND Y OR X AND Z (X OR Y) (W OR Z) = X AND W OR X AND Z OR Y AND Y OR Y AND Z

Question 51

What are the Absorption rules?

Answer 51

X OR (X AND Y) = X X AND (X OR Y) = X