Memory. In the broad sense of the word, it includes all devices that deal with data storage. In its most used meaning, it refers to the primary storage, a fast but temporary type of data storage that the computer uses to store data from programs currently running in your computer and so forth. It can be accessed in any order regardless of its physical location within its circuits. Hence its name: Random Access Memory or RAM.
Secondary storage is also referred to as mass storage. In its most common form, it can be the computer’s hard disk drive, or its compact disk (CD) or digital video disk (DVD) drive. It can store bigger amounts of data than the primary storage, but the data access and transfer times are much slower.
Smart readers will have noticed that these two forms of data storage are complementary, i.e. one has speed but low capacity, and the other capacity but slow speed. This is why they both exist in a computer. All the programs, all the files, documents, pictures, videos, etc. are stored in the secondary data storage device. As needed, the CPU calls for certain data needed for the execution of a program and the data gets transferred into the primary data storage device, where it’s readily available for immediate use without slowing down the computer due to slow access times. Generally speaking, once the computer is done with the data in the primary storage device, it flushes it from it, and writes anything that needs to be kept for future use to the secondary data storage device.
The above oversimplified cycle is, in a nutshell, what the computer is doing when operating. The computer CPU operates on data – it gets the data from the mass storage device and stores it temporarily in the faster storage device – it uses the data to perform its calculations and execute programs – it writes to the mass storage device the results of its calculations and programs execution that need to be stored for future use.
There is only one other thing the computer does, and that is sending data to other devices. That will be the subject of the next few articles.