The term "memory" applies to any electronic component capable of temporarily storing data. There are two main categories of memories:
The main characteristics of a memory are:
The ideal memory has a large capacity with restricted access time and cycle time, a high throughput and is non-volatile.
However, fast memories are also the most expensive. This is why memories that use different technologies are used in a computer, interfaced with each other and organized hierarchically.
Random access memory, generally called RAM is the system's main memory, i.e. it is a space that allows you to temporarily store data when a program is running.
Unlike data storage on an auxiliary memory such as a hard drive, RAM is volatile, meaning that it only stores data as long as it supplied with electricity. Thus, each time the computer is turned off, all the data in the memory are irremediably erased.
Read-only memory, called ROM, is a type of memory that allows you to keep the information contained on it even when the memory is no longer receiving electricity. Basically, this type of memory only has read-only access. However, it is possible to save information in some types of ROM memory.
Flash memory is a compromise between RAM-type memories and ROM memories. Flash memory possesses the non-volatility of ROM memories while providing both read and write access However, the access times of flash memories are longer than the access times of RAM.