Apple DOSApple DOS is the disk operating system for the Apple II computers from late 1978 through early 1983. It was superseded by ProDOS in 1983. Apple DOS has three major releases: DOS 3.1, DOS 3.2, and DOS 3.3; each one of these three releases was followed by a second, minor "bug-fix" release, but only in the case of Apple DOS 3.2 did that minor release receive its own version number, Apple DOS 3.2.1.
Zone bit recordingIn computer storage, zone bit recording (ZBR) is a method used by disk drives to optimise the tracks for increased data capacity. It does this by placing more sectors per zone on outer tracks than inner tracks, which can be achieved by varying the rotational rate (constant linear velocity), the data rate (with constant angular velocity) or a combination of both (using zoned constant angular velocity).Magnetic-tape data storageMagnetic-tape data storage is a system for storing digital information on magnetic tape using digital recording. Commercial magnetic tape products used for data storage were first released in the 1950s and have continued to be developed and released to the present day. Tape was an important medium for primary data storage in early computers, typically using large open reels of 7-track, later 9-track tape.
Floppy diskRemovable disk storage medium8-inch (200 mm), 5.25-inch (130 mm), and 3.5-inch (90 mm) floppy disks8-inch (200 mm), 5.25-inch (130 mm) (full height), and 3.5-inch (90 mm) drivesA 3.5-inch (90 mm) floppy disk removed from its housingA floppy disk, diskette, or floppy diskette is a type of disk storage made from a thin, flexible disk coated with a magnetic storage medium.
Magnetic tapeMagnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic tape can record and play back audio, visual, and digital computer data. Magnetic tape revolutionized sound recording and reproduction and broadcasting.Run-length limitedRun-length limited (RLL) is a line coding technique that is used to send arbitrary data over a communications channel with bandwidth limits. RLL is used in both telecommunication and storage systems that move a medium past a fixed recording head.
Hard disk driveElectro-mechanical data storage deviceHitachi 500GB 3.5" drive, 2011, opened to show the disk platters and read/write armA hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical computer data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnetic material.
Mainframe computerA mainframe computer, informally called a mainframe, maxicomputer, or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing.
Magnetic storageMagnetic storage or magnetic recording is the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetisation in a magnetizable material to store data and is a form of non-volatile memory. The information is accessed using one or more read/write heads. Magnetic storage media, primarily hard disks, are widely used to store computer data as well as audio and video signals.
Computer scienceStudy of computationFundamental areas of computer scienceProgramming language theoryComputer architectureArtificial intelligenceComputational complexity theoryComputer science is the study of computation, information, and automation, together with their associated phenomena.
MicrocomputerA microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a single integrated circuit microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PCB). Microcomputers became popular in the 1970s and 1980s with the advent of increasingly powerful microprocessors such as the MOS Technology 6502, Zilog Z80, and Intel 8088.
Non-return-to-zeroIn telecommunications, a non-return-to-zero (NRZ) line code is a binary code in which ones are represented by one significant condition, usually a positive voltage, while zeros are represented by some other significant condition, usually a negative voltage, with no other neutral or rest condition. For a given data signaling rate, i.e., bit rate, the NRZ code requires only half the baseband bandwidth required by the Manchester code (the passband bandwidth is the same).*As an Amazon Associate I earn from qualifying purchases.