When a computer executes a program, both the code and the data must be able to be located in an element that allows quick access to them and that, in addition, allows us to modify them quickly and flexibly. That element is RAM.
RAM memory (Random Access Memory, random access memory) is a type of volatile memory whose positions can be accessed in the same way.
The latter is highlighted because in computers, and until a certain time, the physical storage media were punched cards or magnetic tapes, whose access was sequential (that is, to reach a certain position X, before we had to go through all the previous positions we want to access). And, as we can speak of memories in all cases, the explicit mention of randomness allows us to specify what type of memory we are referring to.
On the other hand, the term volatile indicates that the content is not maintained once the memory is no longer supplied with electrical energy. This means, plain and simple, that when we turn off the computer, the data in this memory is lost.
That is why, in the case of wanting to preserve the data that we have in RAM memory, we will have to dump it to permanent storage, such as a hard disk, a memory card, or a USB drive, in the form of files.
RAM memory is the "working" memory of the system, which is used at all times to run applications.
The program is read from disk and copied to memory (a procedure called “loading” into memory).
Like all components of modern computers, RAM memory also has its history and has undergone its evolution over time.
The first RAM memories were built, after World War II, using a magnetic material called ferrite.
Being a magnetizable material, they could be polarized in one direction or in the reverse to represent respectively a one and a zero, the representative numbers of the binary logic with which all modern computers work.
At the end of the seventies, the silicon revolution reached the world of computing and, with it, the construction of RAM memories.
The first computers, like the first microcomputers years later, included an amount of RAM that today would seem laughable to us.
For example, the 1981 Sinclair ZX81 was riding 1 Kilobyte, while any smartphone Today's mid-range mounts 1 Gigabyte, which represents one billion (1,000,000,000) bytes.
RAM memory has evolved not only in quantity, but also in access speed and miniaturization.
This evolution of RAM has given rise to different types of technology:
- SRAM (Static Random Access Memory), consisting of a type of memory that can keep data while there is a power supply without needing a refresh circuit.
- NVRAM (Non-Volatile Random Access Memory), which violates the definition we have given of volatile memory, since it can keep the data stored in it even after the electric current is cut off. It is found, in small quantities, in electronic devices for functionalities such as maintaining a configuration.
- DRAM (Dynamic Random Access Memory), which uses capacitor-based technology.
- SDRAM (Synchronous Dynamic Random-Access Memory). The fact that it is synchronous allows it to operate with the same system bus clock.
- DDR SDRAM and, with it, the following DDR2, 3 and 4 evolutions. They consist of a variation of the higher speed SDRAMs. Successive numbers (2, 3 and 4) indicate even higher speeds.
