Random Access Memory
RAM memory is a type of integrated circuit where programs and data are stored. This kind of memory is volatile, i.e. its contents are erased when the circuit is turned off. This is why computers need a mass memory system, like hard disk drives and floppy disks, so we won’t lose our data when the computer is turned off.
The computer processor fetches instructions and data from RAM memory for processing them. When you ”run“ a program what usually happens is the transfer of this program from a mass memory system (hard disk drive, floppy disk, CD-ROM, etc) to RAM memory, and then the processor fetches the instructions and data from the program from RAM memory.
RAM memory circuit can be manufactured under several different technologies such as FPM, EDO, SDRAM and DDR-SDRAM.
Nowadays RAM memory circuits are soldered on small boards called memory modules, which are installed on the computer’s motherboard.
The name ”RAM“ for this kind of memory is not correct, since ROM memories are also random access memories (i.e. you can read any data stored inside the memory circuit in any order you like; the reading cycle doesn’t need to be sequential). The correct name for this kind of memory should be RWM (Read and Write Memory), which makes more sense.
Several other devices also use RAM memories. For example, the video boards use RAM memories to store what is being shown on the display (video memory), printers use RAM memories to store data sent by the computer before they are printed (buffer), CD and DVD recorders use RAM memories to store data sent by the computer before they are recorded on the media, etc.