The Commodore 1581 is a 3½-inch double-sided double-density floppy disk drive that was released by Commodore Business Machines (CBM) in 1987, primarily for its C64 and C128 home/personal computers. The drive stores 800 kilobytes using an MFM encoding but formats different from the MS-DOS, Amiga, and Mac Plus formats. With special software it's possible to read C1581 disks on an x86 PC system, and likewise, read MS-DOS and other formats of disks in the C1581, provided that the PC or other floppy handles the "720 kB" size format. This capability was most frequently used to read MS-DOS disks. The drive was released in the summer of 1987 and quickly became popular with bulletin board system (BBS) operators and other users.
A floppy disk or floppy diskette is an obsolete 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.
Disk density is a capacity designation on magnetic storage, usually floppy disks. Each designation describes a set of characteristics that can affect the areal density of a disk or the efficiency of the encoded data. Such characteristics include modulation method, track width, coercivity, and magnetic field direction.
tomsrtbt is a very small Linux distribution. It is short for "Tom's floppy which has a root filesystem and is also bootable." Its author, Tom Oehser, touts it as "The most GNU/Linux on one floppy disk", containing many common Linux command-line tools useful for system recovery It also features drivers for many types of hardware, and network connectivity.
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.
In computer science, group coded recording or group code recording (GCR) refers to several distinct but related encoding methods for representing data on magnetic media. The first, used in 6250 bpi magnetic tape since 1973, is an error-correcting code combined with a run length limited (RLL) encoding scheme, belonging into the group of modulation codes. The others are different mainframe hard disk as well as floppy disk encoding methods used in some microcomputers until the late 1980s. GCR is a modified form of a NRZI code, but necessarily with a higher transition density.
TRSDOS is the operating system for the Tandy TRS-80 line of eight-bit Zilog Z80 microcomputers that were sold through Radio Shack from 1977 through 1991. Tandy's manuals recommended that it be pronounced triss-doss. TRSDOS should not be confused with Tandy DOS, a version of MS-DOS licensed from Microsoft for Tandy's x86 line of personal computers (PCs).
The IBM eXtended Density Format (XDF) is a way of superformatting standard high-density 3½-inch and 5¼-inch floppy disks to larger-than-standard capacities. It is supported natively by IBM's PC DOS versions 7 and 2000 and by OS/2 Warp 3 onward, using the XDF and XDFCOPY commands.
Micropolis Corporation was a disk drive company located in Chatsworth, California and founded in 1976. Micropolis initially manufactured high capacity hard-sectored 5.25-inch floppy drives and controllers, later manufacturing hard drives using SCSI and ESDI interfaces.
The Commodore 8050, Commodore 8250, and Commodore SFD-1001 are 5¼-inch floppy disk drives manufactured by Commodore International, primarily for its 8-bit CBM and PET series of computers. The drives offered improved storage capacities over previous Commodore drive models.
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.
Distribution Media Format (DMF) is a format for floppy disks that Microsoft used to distribute software. It allowed the disk to contain 1680 KB of data on a 31⁄2-inch disk, instead of the standard 1440 KB. As a side effect, utilities had to specially support the format in order to read and write the disks, which made copying of products distributed on this medium more difficult. An Apple Macintosh computer running Disk Copy 6.3.3 on the Mac OS 7.6 or later operating system can copy and make DMF disks. The first Microsoft software product that uses DMF for distribution were the "c" revisions of Office 4.x. It also was the first software product to use CAB files, then called "Diamond".
Amiga Disk File (ADF) is a file format used by Amiga computers and emulators to store images of floppy disks. It has been around almost as long as the Amiga itself, although it was not initially called by any particular name. Before it was known as ADF, it was used in commercial game production, backup and disk virtualization. ADF is a track-by-track dump of the disk data as read by the Amiga operating system, and so the "format" is really fixed-width AmigaDOS data tracks appended one after another and held in a file. This file would, typically, be formatted, like the disk, in Amiga Old File System (OFS).
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.
Fdformat is the name of two unrelated programs:
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.
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.
