Computer Systems - National 5

Advantages of the Binary System?

There are less rules of arithmetic making it easier to program.

0's and 1's are easier to represent digitally in computer systems.

Any drop in voltage does not affect the data.

What does decimal mean?

Numbers are written in base 10 using the digits 0 to 9.

What does binary mean?

Numbers are written in base 2 using the digits 0 and 1.

What's an integer?

A number with no fractional part.

What is a real number?

A real number is a number that has a fractional part.

How are real number stored?

Floating point representation using a

What's a character?

Any symbol or letter found on a keyboard.

What is a character set?

A character set of a computer is a list of all the characters on a computer can process and store.

What are control characters?

They do not print on the screen in a normal way.

What are printable characters?

They do print on a screen.

What does ASCII stand for?

American Standard Code for Information Interchange

How is (extended) ASCII code stored?

Using one byte (8 bits)

There are two different way of storing graphics what are they?

Bitmaps graphics and vector graphics

How are vector graphics stored?

Vector graphic is made up of objects each having a set of attributes

Examples of objects? (vector graphics)

ellipsis, rectangle, line, polygon

Examples of attributes? (vector graphics)

co-ordinates, line colour, fill colour

What is pixel short for?

picture element

How do bitmap graphics work?

Bitmap graphics work by dividing the image into a 2D array of pixels, then storing a binary value to represent each pixel

What is a resolution?

The amount of pixels that are stored to represent the image.

What is bit depth?

The number of bits used to represent colour or shades of grey in a graphic

How is colour bitmapped graphics stored?

Several bits are assigned to each pixel to represent the colour of the pixel.

What is true colour?

True colour means 24 bits per pixel (the limit at which the human eye can distinguish between colours). This gives a total range of colours.

What is vector type suitable for?

Suitable for graphic, unrealistic images and designs

Advantages of vector type?

• Are easily converted to bitmap formats

• Can be scaled to large sizes keeping original quality

• Files sizes are relatively small

Disadvantages of vector type?

Difficult to create realistic images

Only individual objects can be edited

Dependent on output hardware or software for appearance and quality/

What is bitmap (type) suitable for?

Suitable for natural, hand-drawn, looking realistic images

Advantages of bitmap graphics

Images can be very realistic

Pixel level editing is allowed - allowing effects

Same appearance in all systems regardless of hardware or software

Disadvantages of bitmapped graphics?

Scaling causes pixilation

Only the image as a whole can be edited

Increasing image size needs re-sampling and increases file size

What is the processor called?

Central Processing Unit

What does the ALU - arithmetic logic unit do?

Carries out calculations and makes decisions using logical operations.

What is the control unit?

It controls all parts of the processor and makes sure that program instructions are synchronised to be executed in the correct order.

What is the register?

Registers are storage locations inside the processor chip that hold data while the processor is using it.

What are the two types of registers?

Memory Address Register and Memory Data Register.

What is the MAR?

Memory Address Register - holds the address of the location in memory that is currently being accessed

What is the MDR?

Memory Data Register - holds the contents of the location currently being accessed.

How is memory organised inside a computer?

Memory is organised as a series of storage locations each with its own unique address.

What is RAM?

Random Access Memory. This is called volatile memory which means that it hold it data as long as the computer is switch on

What is ROM?

Read Only Memory - this is called non-volatile memory which means that it holds its data permanently even when the computer is switched off.

What is a bus?

Buses are sets of wires connecting parts of the computer together.

What is a data bus?

A data bus transfers data between the main memory and the processor and it's bi-directional.

What is an address bus?

The address bus indicates which address in memory is being read from or written to.

What are the two forms of high-level language translator?

Interpreters and Compilers

What is an interpreter?

Interpreter is a high level translator which translates and executes each line of the program in turn.

What a disadvantage of a interpreter?

The run (execution) is slower because of the simultaneous translation and because any repeated line will be re-translated.

What is an advantage of a interpreter?

It is easier to locate errors since the interpreter can highlight lines in the source code.

What are compilers?

Compiler translates all of your high level language code, called source code, into machine code all at once

Advantages of the compiler?

Much faster to run. It uses less memory.

Disadvantages of the compiler?

All errors need to have been corrected before source code can be compiled to run independently.

Solutions to reduce carbon emissions?

Use low-power computing devices. Adjusting the monitor settings. Power-down settings.

What is a firewall?

A firewall serves as a barrier to protect a network or system from unauthorised access

What is encryption?

In cryptography, encryption is the data held on a computing system is put into code. This means if the data is hacked into, it is meaningless to the hacker unless they have the security key to unlock or decipher the encrypted data

What are the four acts you must be aware of?

The Computer Misuse Act. Copyright Designs and Patents Act 1988. UK General Data Protection Regulation. Communications Act.

Standby (sleep) mode features?

RAM continues to be powered.

Data for software running at the time of standby is temporarily stored until user resumes work.

Power to all other component is significantly reduced or turned off completely.

Hibernate mode?

Contents of RAM are copied to the hard disk

Hard disk saves a permanent copy

Can turn almost all component off or down to a level or very low energy use

Features of a firewall?

Network Security System, Traffic Filter, Monitoring Tool.

Network Security System?

A firewall monitors and controls incoming and outgoing network traffic based on predetermined security rules

Traffic Filter?

It filters traffic based on IP addresses, protocol, ports and other criteria allowing only authorised communication to pass through.

Monitoring Tool

A firewall monitors network traffic, identifying and logging potential security threats for further analysis

Personal data?

Any data that can be used to identify an individual directly is personal data.

Data subject?

The term data subject refers to the individual whose data is being collected.

Data controller?

The data controller is the company/organisation that is using personal data and managing how that data is processed

Privacy notice?

A privacy notice is the information provided by the data controller that tells the data subject how their information will be processed and how long it will be kept.

The main computing issues are within communications acts are?

Piggybacking, Threatening behaviour online, offensive indecent images.

7 order of the general data protection regulations?

1. processed lawfully, fairly

2. used for the declared purpose only

3. limited to the data needed for the declared purpose

4. accurate

5. not kept for longer then necessary

6. held securely

7. accountability