Disk swapping refers to the practice of inserting and removing, or swapping,

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a ...

s in a

floppy disk drive A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a ...

-based

computer A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...

system. In the early days of

personal computer A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ...

s, before

hard drives A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...

became commonplace, most fully outfitted computer systems had two floppy drives (addressed as A: and B: on

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few op ...

, and also on

CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/Intel 8085, 85-based microcomputers by Gary Kildall of Digital Research, Dig ...

other systems had different conventions). Disk drives were expensive, however, and having two was seen as a luxury by many computer users who had to make do with a single drive. The purpose of two floppy drives was so that the disk containing the

application Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a ...

program could remain in the drive while the data disk containing the user's files could be accessed in the second drive. Without a second drive, in order to use a function of the program not loaded into memory, the user would have to first remove the data disk, then insert the program disk. When the user then wanted to save their file, the reverse operation would have to be performed. On some less-than-

user-friendly Usability can be described as the capacity of a system to provide a condition for its users to perform the tasks safely, effectively, and efficiently while enjoying the experience. In software engineering, usability is the degree to which a softw ...

systems, this could result in

data loss Data loss is an error condition in information systems in which information is destroyed by failures (like failed spindle motors or head crashes on hard drives) or neglect (like mishandling, careless handling or storage under unsuitable conditions) ...

when, for example, files were accidentally saved onto the program disk. Disk swapping was an infamous feature of early

Macintosh 128K The Macintosh, later rebranded as the Macintosh 128K, is the original Mac (computer), Macintosh personal computer from Apple Inc., Apple. It is the first successful mass-market All-in-one computer, all-in-one desktop personal computer with a gr ...

systems, which were extremely

RAM Ram, ram, or RAM most commonly refers to: * A male sheep * Random-access memory, computer memory * Ram Trucks, US, since 2009 ** List of vehicles named Dodge Ram, trucks and vans ** Ram Pickup, produced by Ram Trucks Ram, ram, or RAM may also ref ...

-starved.

References

{{reflist Floppy disk computer storage