1. A Dummies guide to computer memory

2. Ram and Rom
ROM is a type of memory that saves data even when the computer is switched off.
ROM (Read Only Memory) is a type of memory which stores the instructions which the computer uses when it switches on – the BIOS (basic input output system).
Because the data is stored permanently, it is called “non – volatile memory”
There may be many ROM chips in a computer. They are attached to the Motherboard.

3. Ram and Rom
If a computer loses power, all data stored in its RAM is lost.
Examples of what is stored in RAM:
The operating system
Applications
The graphical user interface (GUI)
RAM (Random Access Memory) is a fast temporary type of memory in which programs, applications and data are stored.
Because data is lost when the computer is switched off, it is called “volatile memory”

4. Pc performance
The more RAM your computer has, the faster the programs on your computer will run.
RAM has two main attributes that can affect a computer’s performance: memory capacity and memory speed.
If you have a lot of windows or different applications running, you might find that your system starts to slow down. This is because your RAM is full up and it is having to decide what it needs to keep stored in memory and what it can release.
you can improve the performance of your computer by installing extra RAM.

5. Virtual memory is a method of making a computer appear to have more memory than it really has. For instance a PC might have 2Gb of RAM as primary memory, but virtual memory of 4Gb.
Virtual memory
Virtual memory can damage the hard drive of a computer, because it is being overworked; this is called thrashing.
Virtual memory is very slow compared to 'real' RAM and so the operating system may give a warning such as 'you are low on virtual memory, please close some applications'.

6. Flash and cache memory Flash can be found in many forms Memory sticks
Jump Drives
Camera memory cards
Solid state hard drives.
Flash memory is a type of non-volatile storage. It retains its information even without power. So it is ideal for devices such as cameras and solid state drives.
Flash memory uses a relatively large electric current to force electrons through a barrier and trap them on the other side until they are reset

7. Flash and cache memory
Two types of caching are commonly used in personal computers: memory caching and disk caching.
Cache can be either a reserved section of main memory or an independent high-speed storage device.
Cache memory, sometimes called a cache store or RAM cache, is a portion of memory made of high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM) used for main memory.