The Commodore 1541 is a floppy disk drive which was made by Commodore International for the Commodore 64 (C64), Commodore's most popular home computer. The best-known floppy disk drive for the C64, the 1541 is a single-sided 170-kilobyte drive for 5¼" disks. The 1541 directly followed the Commodore 1540.
Disk storage is a general category of storage mechanisms where data is recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotating disks. A disk drive is a device implementing such a storage mechanism. Notable types are today's hard disk drives (HDD) containing one or more non-removable rigid platters, the floppy disk drive (FDD) and its removable floppy disk, and various optical disc drives (ODD) and associated optical disc media.
A floppy disk or floppy diskette 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 fabric that removes dust particles from the spinning disk. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive (FDD) connected to or inside a computer or other device.
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 magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small rectangular box.
The ST-506 and ST-412 were early hard disk drive products introduced by Seagate in 1980 and 1981 respectively, that later became construed as hard disk drive interfaces: the ST-506 disk interface and the ST-412 disk interface. Compared to the ST-506 precursor, the ST-412 implemented a refinement to the seek speed, and increased the drive capacity from 5 MB to 10 MB, but was otherwise highly similar.
Shugart Associates was a computer peripheral manufacturer that dominated the floppy disk drive market in the late 1970s and is famous for introducing the 5+1⁄4-inch "Minifloppy" floppy disk drive. In 1979 it was one of the first companies to introduce a hard disk drive form factor compatible with a floppy disk drive, the SA1000 form factor compatible with the 8-inch floppy drive form factor.
Disk formatting is the process of preparing a data storage device such as a hard disk drive, solid-state drive, floppy disk, memory card or USB flash drive for initial use. In some cases, the formatting operation may also create one or more new file systems. The first part of the formatting process that performs basic medium preparation is often referred to as "low-level formatting". Partitioning is the common term for the second part of the process, dividing the device into several sub-devices and, in some cases, writing information to the device allowing an operating system to be booted from it. The third part of the process, usually termed "high-level formatting" most often refers to the process of generating a new file system. In some operating systems all or parts of these three processes can be combined or repeated at different levels and the term "format" is understood to mean an operation in which a new disk medium is fully prepared to store files. Some formatting utilities allow distinguishing between a quick format, which does not erase all existing data and a long option that does erase all existing data.
Modified frequency modulation (MFM) is a run-length limited (RLL) line code used to encode data on most floppy disks and some hard disk drives. It was first introduced on hard disks in 1970 with the IBM 3330 and then in floppy disk drives beginning with the IBM 53FD in 1976.
IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible for many of the innovations in these products and their technologies. The basic mechanical arrangement of hard disk drives has not changed since the IBM 1301. Disk drive performance and characteristics are measured by the same standards now as they were in the 1950s. Few products in history have enjoyed such spectacular declines in cost and physical size along with equally dramatic improvements in capacity and performance.
A disk enclosure is a specialized casing designed to hold and power hard disk drives or solid state drives while providing a mechanism to allow them to communicate to one or more separate computers.
The Rainbow 100 is a microcomputer introduced by Digital Equipment Corporation (DEC) in 1982. This desktop unit had a monitor similar to the VT220 and a dual-CPU box with both 4 MHz Zilog Z80 and 4.81 MHz Intel 8088 CPUs. The Rainbow 100 was a triple-use machine: VT100 mode, 8-bit CP/M mode, and CP/M-86 or MS-DOS mode using the 8088. It ultimately failed to in the marketplace which became dominated by the simpler IBM PC and its clones which established the industry standard as compatibility with CP/M became less important than IBM PC compatibility. Writer David Ahl called it a disastrous foray into the personal computer market. The Rainbow was launched along with the similarly packaged DEC Professional and DECmate II which were also not successful. The failure of DEC to gain a significant foothold in the high-volume PC market would be the beginning of the end of the computer hardware industry in New England, as nearly all computer companies located there were focused on minicomputers for large organizations, from DEC to Data General, Wang, Prime, Computervision, Honeywell, and Symbolics Inc.
Floppy disk format and density refer to the logical and physical layout of data stored on a floppy disk. Since their introduction, there have been many popular and rare floppy disk types, densities, and formats used in computing, leading to much confusion over their differences. In the early 2000s, most floppy disk types and formats became obsolete, leaving the 3+1⁄2-inch disk, using an IBM PC compatible format of 1440 KB, as the only remaining popular format.
A floppy-disk controller (FDC) has evolved from a discrete set of components on one or more circuit boards to a special-purpose integrated circuit or a component thereof. An FDC directs and controls reading from and writing to a computer's floppy disk drive (FDD). The FDC is responsible for reading data presented from the host computer and converting it to the drive's on-disk format using one of a number of encoding schemes, like FM encoding or MFM encoding, and reading those formats and returning it to its original binary values.
A bit nibbler, or nibbler, is a computer software program designed to copy data from a floppy disk one bit at a time. It functions at a very low level directly interacting with the disk drive hardware to override a copy protection scheme that the floppy disk's data may be stored in. In most cases the nibbler software still analyses the data on a byte level, only looking to the bit level when dealing with synchronization marks (syncs), zero-gaps and other sector & track headers. When possible, nibblers will work with the low-level data encoding format used by the disk system, being Group Coded Recording, Frequency Modulation, or Modified Frequency Modulation.
IMG, in computing, refers to binary files with the .img filename extension that store raw disk images of floppy disks, hard drives, and optical discs or a bitmap image – .img.
The Disk II Floppy Disk Subsystem, often rendered as Disk ][, is a 5 +1⁄4-inch floppy disk drive designed by Steve Wozniak at the recommendation of Mike Markkula, and manufactured by Apple Computer, Inc. It went on sale in June 1978 at a retail price of US$495 for pre-order; it was later sold for $595 including the controller card and cable. The Disk II was designed specifically for use with the Apple II personal computer family to replace the slower cassette tape storage. These floppy drives cannot be used with any Macintosh without an Apple IIe Card as doing so will damage the drive or the controller.
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium encased in a rectangular plastic carrier. It is read and written using a floppy disk drive (FDD). Floppy disks were an almost universal data format from the 1970s into the 1990s, used for primary data storage as well as for backup and data transfers between computers.
The Macintosh External Disk Drive is the original model in a series of external 3+1⁄2-inch floppy disk drives manufactured and sold by Apple Computer exclusively for the Macintosh series of computers introduced in January 1984. Later, Apple would unify their external drives to work cross-platform between the Macintosh and Apple II product lines, dropping the name "Macintosh" from the drives. Though Apple had been producing external floppy disk drives prior to 1984, they were exclusively developed for the Apple II, III and Lisa computers using the industry standard 5+1⁄4-inch flexible disk format. The Macintosh external drives were the first to widely introduce Sony's new 3+1⁄2-inch rigid disk standard commercially and throughout their product line. Apple produced only one external 3+1⁄2-inch drive exclusively for use with the Apple II series called the Apple UniDisk 3.5.
A floppy disk hardware emulator or semi-virtual diskette (SVD) is a device that emulates a floppy disk drive with a solid state or network storage device that is plug compatible with the drive it replaces, similar to how solid-state drives replace mechanical hard disk drives.
The floppy disk is a data storage and transfer medium that was ubiquitous from the mid-1970s well into the 2000s. Besides the 3½-inch and 5¼-inch formats used in IBM PC compatible systems, or the 8-inch format that preceded them, many proprietary floppy disk formats were developed, either using a different disk design or special layout and encoding methods for the data held on the disk.
