3. RAM

RAM acts as a temporary store for program instructions and data. It can only store things temporarily because it is volatile - it must constantly be powered or it will lose any data it is holding.

It is useful as a temporary store because any data or instructions in RAM can be accessed in any order, i.e. it can be accessed non sequentially. This is why it is called Random Access Memory.

Because the CPU can access any memory location at any time, programs held in RAM can run very quickly.

In summary:

• RAM is used as main memory. It is accessed directly by the CPU
• RAM is volatile memory. If it loses power, the data it holds is lost
• RAM holds billions of storage locations, each with its own memory address. These can be accessed in any order. This is why it is Random Access Memory

The photo below shows a typical RAM module. It is slotted into a socket on the motherboard. This is why it is fairly simple to change or upgrade RAM in a computer as you just swap out the memory module.