The Random Acces Memory (RAM) is the main form of storage on your computer. It stores all your memory, and allows you to be able to acces it in any order. Unlike the Serial Acces Memory (SAM) that stores data as a series of memory or like an old cassette tape which can only be accesed in a sequential form. The RAM also provides you with enough space for your computer to read and write data that can later be accesed by the CPU (Central Processing Unit).
It gets the name "Random Acces" because it allows you to acces any memory cell, directly. A memory cell is a single bit of data, these cells are what make up the memory in the RAM. The data that is stored in your RAM is there as long as your computer is turned on, once the computer is shot off the stored memory disappears. When you turn your computer back on it uses instructions that are stored in chips called ROM chips that then read your operating system and load your memory back into your RAM.The first RAM's built were in 1951 but weren't sold until the late 1960's to the early 1970's. Since then the RAM is the best form of memory storage on a computer, which is why its many times refered to as the memory of a computer.