Primary memory is the memory that a computer uses to store data that is actively being used or processed by the CPU. The CPU is the part of the computer that processes the information, executes instructions from programs, performs calculations, and manages data flow to and from other parts of the computer. Primary memory is a volatile type of memory, meaning that it loses its contents when the computer is turned off. Primary memory is characterised by its high speed and direct accessibility by the CPU.

Characteristics of Primary Memory:

Volatile: Data is lost when power is turned off.
Fast Access: Provides quick read and write access to data, which is crucial for the CPU to perform tasks efficiently.
Temporary Storage: Holds data and instructions that the CPU needs while performing tasks. Once the task is completed, data can be written back to secondary storage or discarded.
Limited Capacity: Typically smaller in size compared to secondary storage (like hard drives or SSDs).

Types of Primary Memory:

RAM (Random Access Memory):

• Dynamic RAM (DRAM): Needs to be refreshed thousands of times per second.
• Static RAM (SRAM): Faster and more reliable than DRAM, but more expensive.

ROM (Read-Only Memory):

• Non-volatile memory used to store firmware (software that is closely tied to specific hardware and unlikely to need frequent updates).
• Includes PROM, EPROM, and EEPROM types, which can be programmed and in some cases reprogrammed.

Usage in Computing:

Running Applications: Primary memory stores the operating system, applications, and data currently in use to allow for quick access and processing.
Buffering and Caching: Used to buffer and cache data to improve performance and speed of data retrieval and processing.

In a computer, all data is stored in binary form. Binary is a number system that only contains the numbers 0 and 1. Therefore, a binary digit has two possible states, 0 or 1.

A single binary digit is known as a bit. A bit is the smallest unit of data that a computer can use.

A byte is another unit of binary data. One single byte is made up of 8 bits.

The binary unit system:

Unit	Size
0.125 bytes	1 bit
0.5 bytes	4 bits
1 byte	8 bits
1 kilobyte	1000 bytes
1 megabyte	1000 kilobytes
1 gigabyte	1000 megabytes
1 terabyte	1000 gigabytes
1 petabyte	1000 terbytes

4 bits or 0.5 bytes is known as a nibble.

Ethics are moral principles that govern a person's behaviour or the conducting of an activity.

Ethical issues in computers include:

• Public safety
• Data security

New technologies must not compromise the safety of its users.

For example, driverless cars have to ensure the safety of passengers, pedestrians and other drivers.

Personal data is very precious and so needs to be kept secure. Hackers are people that attempt to break into systems in order to steal peoples' personal data. Malware may also be used to obtain data. Malware is any software that is designed to steal data or cause damage to computers. Ransomware is an increasing used type of malware which when installed on a computer is designed to encript data, denying users access to this data unless a ransom is paid. The government and other agencies do not encourage paying the ransom, as this encourages hackers to continue carrying out these acts.

Legal Issues

Computer usage has brought about new crimes. With the rise of the internet, there is an increasing amount of illegal activities being carried out using computers.

Some examples of how computers are used illegally:

• Illegally sharing others' personal data
• Stealing financial information
• Illegally copying and distibuting copyrighted media
• Extortion or blackmail

In the UK, there are several laws to combat illegal activities on the internet:

• The Copyright, Designs and Patents Act 1988 - gives the creator of published material the control over the way it is used.
• The Computer Misuse Act 1990 - Defines and criminalises a number of offences involving the use of a computer.
• The Data Protection Act 1998/2018 - governs the protection of personal data in the UK.
• Freedom of Information Act 2000 - gives the public the right to access information recorded by public sector organisations.
• Creative Commons Licensing - one of several copyright licences that allows free sharing and distribution of a product.

The Copyright, Designs and Patents Act 1988