Mr Hylton J277 Unit 1

Legal Issues

The Data Protection Act 2018 Computer Misuse Act 1990 Copyright Designs and Patents Act 1988

Cultural issues

The way that Computer Science can impact the way people groups do things

Privacy Issues

Collecting storing and disseminating information about individuals

Data Protection Act 2018

A law covering:

what can be collected

how long it can be kept for

steps to keep it up to date/accurate

sending and using the data

who can see that data

Computer Misuse Act 1990

The UK law that makes it illegal to hack into a person's computer and to disrupt deliberately someone else's computer.

Copyright Designs and Patents Act

Legislation concerned with the distribution of ideas, media or products. If you did not make it, you cannot sell, or share it without the creator/owners permission

Software Licenses

Open Source & Proprietary

Open source

The source code is free and accessible by all. There is no legal cover or protection. Can be better as it is maintained by an entire community. Updates and addons are created and you can personalise it

Proprietary

Effectively the opposite of open source. Usually not free

Malware

software that is intended to damage or disable computers and computer systems.

Brute Force attack

An attack on passwords or encryption that tries every possible password or encryption key.

Social engineering

People as a weak point

denial of service attack

a cyber attack in which an attacker sends a flood of data packets to the target computer

Data interception and theft

Seizing data as it is in transit

SQL Injection

An attack that targets SQL servers by inserting commands to be manipulated by the database.

Penetration Testing

Professional hacking to access data and computing power without being granted access; hired to identify and repair vulnerabilities and only work once

Anti-malware

A utility that searches for and removes any malware on a computer.

Firewalls

software to prevent unauthorized users

User Access Levels

A network policy that defines which users can see which folders and files and the type of access they have to them. Eg: Read-Only or Read-Write.

Passwords

A method of authentication where a person must enter a secrect string of characters

Strong password

"8 or more characters

Contain a number

Contain a letter

Contain a upper case character

Contain a lower case character

Contain a special character"

Encryption

Process of converting readable data into unreadable characters to prevent unauthorized access.

Operating System (OS)

the software that allows users to interface with the computer

Functions of an operating system

User management

memory management/multitasking

peripheral management and drivers

file management

memory management / multitasking

A function of the operating system that controls the CPU and RAM so that programs run simultaneously and concurrently

Peripheral Management

A function of the operating system which manages the input to the CPU and the output from external devices

User Management

An operating system feature that allows user accounts to be created and managed

File Management

A function of the operating system that organises and controlling files

Utility Software

software that performs some sort of maintenance on the computer system

Encryption software

software that scrambles data into a secret code that can only be broken by complicated mathematical algorithms

Defragmentation

A utility that reduces the amount of fragmentation by physically moving data on the disk to store the pieces of each file contiguously

Data Compression

Reducing the amount of space needed to store a piece of data

LAN

Local Area Network; a geographic network that covers a relatively small geographic area.

WAN

Wide Area Network; a geographic network that covers a relatively large geographic area.

Factors that affect the performance of networks

Number of devices connected

Bandwidth

Bandwidth

The amount of data that can be send across a network per second (speed of a network)

client/server network

A network that uses centrally administered computers

peer-to-peer network

A type of network that connects client computers directly together. All computers are equal

The hardware needed to connect stand-alone computers into a Local Area Network

Routers

Switches

NIC (Network Interface Controller/Card)

Transmission media

Wireless access points Network Interface Card (NIC)

Wireless access points

Allows you to wirelessly access a network (Wifi)

Network Interface Card (NIC)

An expansion card that enables a computer to connect other computers / a network

Transmission media

Wifi\Wireless

DNS server

translates the domain name into its associated IP address

The cloud

Data and programs are stored on the internet. They can be accessed anytime from any computer with internet access.

Router

A device that transfers data from one network to another

Switch

Transfers data around a network

Hosting

Storing files or data on another computer (e.g webpage files) to be accessed by other

Layers

Divisions of functionality within a network

Application Layer

Transport Layer

Internet Layer

Network Access Layer/Data Link Layer

Application Layer

The 1st layer of the TCP/IP model. This layer's protocols enable software programs to negotiate formatting

Transport Layer

The 2nd layer of the TCP/IP model. In this layer protocols ensure that data are transferred from point A to point B reliably and without errors. this layer services include flow control

Internet Layer

The 3rd layer of the TCP/IP model.Responsible for addressing

Data Link Layer

The 4th layer of the TCP/IP model. This layer bridges the networking media with the Network layer. Its primary function is to divide the data it receives from the Network layer into frames that can then be transmitted by the Physical layer.

Packet

Data broken down to be sent across a WAN.

ROM

Non volatile. Stores start up instructions

RAM/Main Memory

Volatile. Stores data for programs that are currently open

The difference between RAM and ROM

RAM is volatile ROM is not

Virtual memory

Using part of your secondary storage as primary storage (RAM)

Why would you use virtual memory?

Not enough RAM\memory

Secondary Storage

Long term storage. Auxiliary (external) to the computer

Optical Storage

storage device that records data by burning microscopic holes in the surface if the disk with a laser. E.g CD DVD Blu ray.

Small capacity

Slow

Speed

Portable

Can get scratch

Cheap

Magnetic Storage

Type of secondary storage that users magnets to read and store data. Examples include floppy disks and hard disks.

High capacity

Average

Speed

Not portable

Moving parts-can get broken not very durable

Quite reliable

Cheap

Solid state

Storage that uses transistors to store data. It has no moving parts. E.g USB memory

High capacity but limited

Fast speed

Portable

No moving parts, so it is durable

It is reliable

Expensive

Capacity

How big your storage is.

Speed

How fast the storage device is

Portability

Whether the device can be carried around

Durability

How robust the device is

Reliability

How much you can rely on your device to work

Cost

How expensive the storage device is

Characteristic of secondary storage

Capacity, speed, portability, durability, reliability and cost

bit

A single binary digit: 1 or 0

Nibble

4 bits or half a byte

Byte

8 bits

Kilobyte

1000 bytes

Megabyte (MB)

1000 kilobytes or 1,000,000 bytes

Gigabyte (GB)

1,000 megabytes or 1,000,000,000 bytes

Terabyte (TB)

1,000 gigabytes or 1,000,000,000,000 bytes

Petabyte

1,000 terabytes or 1,000,000,000,000,000 bytes

ASCII

8 bit binary Character set representing keyboard characters. Can represent 255 characters

Unicode

A character set which can have 32 bit(varies in size). This enables more languages to be represented but each character takes up more storage.

Character set

A list of the characters and the codes used to represent each one

Binary shift

Allows you to easily multiple and divide base-2 binary numbers. A left shift multiplies by 2 and a right shift divides by 2.

Images

Made up of pixels. Each pixel contains binary data representing a different colour

Pixel

A "picture element" containing binary data representing a colour

Short for "picture element" it is the fundamental unit of a digital image

Each pixel contains binary information on its colour

Meta Data

a set of data that describes and gives information about the file

E.g name

width and height (images)

Colour depth

The number of bits used for each pixel

As it increases the quality of the image increases

so does the file size.

Resolution

The dimensions of the grid that forms a bitmap graphic.

Sample

The height of the wave length is measured at regular intervals

Bit rate

The amount of data sampled per second. Sample rate * bit depth

Sample frequency/rate

The number of samples made per second. 1 sample per second = 1 hertz

Bit depth

The number of bits used to record each sample.

Compression

Making a file smaller by removing unneeded data

Lossy Compression

Removing data that will not be noticed, to reduce the file size. It is irrecoverable

Lossless Compression

Removing data that will not be noticed, to reduce the file size. The original data can be reconstructed

The playback quality

As quality increases the quality of the sound and file size increases

Image quality

As quality increases the quality of the image and file size increases

CPU

The brain of the computer. Carries out instructions. It fetches

MAR

MDR. Program Counter (PC) and Accumulator (ACC) are all parts of the

Memory Address Register (MAR)

Stores the location for data to be fetched from or sent to memory