Computer Systems

Question 1

What is binary code

Answer 1

Any data that is stored inside a computer ends up as a collection of 0’s and 1’s.
•This is called binary, but is sometimes referred to as machine code.

Question 2

What is floating point representation

Answer 2

Floating point representation involves using two parts to store a number, the mantissa and the exponent.

Question 3

What is the mantissa and exponent

Answer 3

The mantissa is used to store the accuracy/precision of a number.(number after decimal)

The exponent is used to store the range of a number.(2°) the ° is the exponent

Question 4

What are bitmap graphics

Answer 4

A bitmap graphic is one that stores every single pixel on the screen.

•Bitmaps are simple images that do not contain any layers, are resolution dependent and do not resize well.

Question 5

Disadvantages of bitmap graphics

Answer 5

Bitmaps are simple images that do not contain any layers, are resolution dependent and do not resize well.

Question 6

Pros of bitmap graphics

Answer 6

They can be very detailed in quality so are good for storing photographs and detailed editing but can have large file sizes.

Question 7

What is a vector graphic

Answer 7

Vector graphics are made up of shapes

Vectors are stored by their objects and attributes using a mathematical formula.

Question 8

What are objects and attributes

Answer 8

An object would be the shape that is being drawn. For example, rectangle, ellipse, line, polygon.

An attribute would be how to draw the object. For example, starting x and y coordinates, fill colour, line colour, thickness, curve.

Question 9

Examples of objects and attributes

Answer 9

There are several common objects that you need to know how they are represented. These are:
Rectangle
Ellipse
Line
Polygon

For each of these you need to know how the attributes of:
co-ordinates
line colour
fill colour

Question 10

Pros of vector graphics

Answer 10

Vector graphics can be layered.

They can be resized without loss of quality

They are resolution independent.

They tend to have smaller file sizes.

Question 11

Disadvantages of vector graphics

Answer 11

Cannot edit individual pixels.

Complex graphics with lots of layers can take up a lot of storage space.

Best suited to logos, line drawings, cartoons, simple illustrations.

Question 12

Components computers need to run

Answer 12

Input, Output and Backing Storage Devices
Processor
Memory
Buses

Question 13

What are Backing storage devices

Answer 13

Backing storage devices are used to store data and programs when it is not being used.
Hard drive
CD’s

Question 14

What is the processor

Answer 14

A Processor is the ‘brain’ of the computer and it carries out the operations the computer performs.

This is usually done on a single microchip.

Question 15

What is the arithmetic and logic unit(ALU)

Answer 15

Arithmetic and Logic Unit (ALU) – Performs arithmetic calculations, logical functions and makes decisions. (IF AND OR NOT < >)

Question 16

What is the control unit

Answer 16

Control Unit – Controls other parts of the processor, the timings of operations and sends out signals to fetch, interpret and execute instructions from main memory. It makes sure everything happens in the correct place at the correct time.

Question 17

What are registers

Answer 17

Registers – Temporary storage locations for data being used by the processor, this includes data being processed and instructions being carried out.

Question 18

The 3 parts of the processor are

Answer 18

Arithmetic and logic unit(ALU)
Control unit
Registers

Question 19

What is memory

Answer 19

The purpose of memory is to store programs and data currently being used by the processor. The more programs/data that can be held at one time, the faster the computer can operate.

Question 20

What are the two types of memory

Answer 20

There are two types of memory:
RAM, Random Access Memory
ROM, Read Only Memory

Question 21

What is RAM

Answer 21

RAM is volatile, which means it holds data for as long as the computer is turned on. It is lost when the computer is turned off.
RAM holds programs and data being processed. It also holds the Operating System when the computer is running.

Question 22

What is ROM

Answer 22

ROM – Read Only Memory
ROM is non volatile, which means it is not lost when the computer is turned off.
Used to store data and program permanently and cannot be altered - It is usually set when the chip is manufactured.
Stores the bootstrap loader of the Operating System, one of the most important programs on a computer. When the computer is turned on the bootstrap loader makes the OS load so that you can use the computer.

Question 23

Purpose of unique addresses

Answer 23

Every item that is saved in memory has a unique location so that it can be opened and found again.

Question 24

What are buses

Answer 24

Different parts of the processor communicate using buses, which are the sets of wires connecting the processor to other parts of the computer system.

Different buses have a different job to do.

Question 25

Purpose of data bus

Answer 25

Carries data to and from the processor, main memory or any other devices attached to it.

Question 26

Purpose of address bus

Answer 26

Address Bus – Pinpoints a memory location in memory. It is a uni-directional bus, which means it can only go one way, from the processor to the memory location.

Question 27

Purpose of control bus

Answer 27

Control Bus – is a collection of different wires which all have separate functions, including clock, reset and write. These functions will:
Clock: carry the clock pulses to keep the processor running at the correct speed.
Reset: Stop the current program and cause the computer to reboot.
Write: To write data from the processor to a memory location.

Question 28

Methods of translating program

Answer 28

Interpreter
Compiler

Question 29

What is an interpreter

Answer 29

An interpreter works by translating and excuting one line of code at a time.
This means that it can help the user to identify coding errors.
If this method is used the program will need to be translated every time it is run.
This means that the interpreter will also need to be present in memory every time the program is run.

Question 30

What is a compiler

Answer 30

A compiler works by translating all the code at once.
The program is called the source code and when it has been translated it is called the object code.
The object code can be saved and used over and over again.
This means that the compiler does not need to be present in memory every time the program is run.
But if changes are made to the program it will need to be retranslated.

Question 31

how can the negative effect of computer systems be offset?

Answer 31

Adjusting the settings on monitors
Using automatic power down settings
Not leaving devices on standby

Question 32

What is malware

Answer 32

Malware is short for malicious software and it is a type of software that is designed to disrupt computer operations, or the running of a computer. Malware is a general term used to describe any software or code that exploits a computer or the information on a computer without the user’s consent. Malware includes viruses, worms and Trojan Horses.

Question 33

What is a virus

Answer 33

A virus is a small piece of software that piggybacks on real programs. Piggybacking means that it attaches itself to the piece of real code and gets downloaded or opened when the real code is downloaded or opened. For example, a virus might attach itself to a program such as a spread sheet program. Each time the spread sheet program runs, the virus runs, too, and it has the chance to reproduce (by attaching to other programs) or wreak havoc.

Question 34

What is phishing

Answer 34

Phishing is a way of trying to get information like usernames and passwords or log in details from users.
Phishing emails are often of a very high quality and they will pretend to be from a well-known bank or Internet site. When the user clicks on a link in the email they will be taken to a fake website and encouraged to enter their personal information and bank or credit card details. These details can then either be sold to other companies or used to take money from your bank account

Question 35

What is a firewall

Answer 35

A firewall is either software or hardware and is used to try and maintain the security of a network. Its aim is to monitor and control the data that comes in and out of the network and to identify any data that should not be there, or might be a threat.
A firewall forms a barrier between the internal secure network and any other network, such as the Internet. You can imagine it as a type of wall that will stop data such as a virus, or a hacker from entering into the network.

Question 36

What is encryption

Answer 36

Encryption is where a code is applied to a file or email before it is sent.
This means that if the email is intercepted it cannot be read by someone else unless they have the code to decipher the email or file.
If they try to read the email it will appear scrambled and mean nothing.

Question 37

Public/private keys encryption method

Answer 37

Everyone has a key that they make public – so any one can use it.
If you want to email a person you encrypt the email using their public key. Then you send it.
They are the only person that can open the encrypted email – using their private key.
No one else ever knows their private key!