|
Floppy Disk 2009 G1
A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent 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. The first floppy disks, invented and made by IBM, had a disk diameter of . Subsequently, the 5¼-inch and then the 3½-inch became a ubiquitous form of data storage and transfer into the first years of the 21st century. 3½-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5¼-inch, 8-inch, and other-size floppy disks are rare to non-existent. Some individuals and organizations continue to use older equipment to read or transfer data from floppy disks. Floppy disks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floppy Disk 2009 G1
A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent 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. The first floppy disks, invented and made by IBM, had a disk diameter of . Subsequently, the 5¼-inch and then the 3½-inch became a ubiquitous form of data storage and transfer into the first years of the 21st century. 3½-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5¼-inch, 8-inch, and other-size floppy disks are rare to non-existent. Some individuals and organizations continue to use older equipment to read or transfer data from floppy disks. Floppy disks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floppy Disk Drive 8 Inch
A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent 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. The first floppy disks, invented and made by IBM, had a disk diameter of . Subsequently, the 5¼-inch and then the 3½-inch became a ubiquitous form of data storage and transfer into the first years of the 21st century. 3½-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5¼-inch, 8-inch, and other-size floppy disks are rare to non-existent. Some individuals and organizations continue to use older equipment to read or transfer data from floppy disks. Floppy disks w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM PC Convertible
The IBM PC Convertible (model 5140) is a laptop computer made by IBM, first sold in April 1986. The Convertible was IBM's first laptop-style computer, following the luggable IBM Portable, and introduced the 3½-inch floppy disk format to the IBM product line. Like modern laptops, it featured power management and the ability to run from batteries. It was replaced in 1991 by the IBM PS/2 L40 SX, and in Japan by the IBM Personal System/55note, the predecessor to the ThinkPad. Predecessors IBM had been working on a laptop for some time before the Convertible. In 1983, work was underway on a laptop similar to the Tandy Model 100, codenamed "Sweetpea," but it was rejected by Don Estridge for not being PC compatible. Another attempt in 1984 produced the "P-14" prototype machine, but it failed to pass IBM's human factors tests, especially after poor public reception of the display in the competing Data General-One. Description The PC Convertible came in three models: PC Convertible, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Density
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. 8-inch media ''Single density'' (SD or 1D) describes the first generation of floppy disks that use an iron oxide coating. Floppy drives utilize 300-oersted write heads, FM encoding, and a track width of for a density of 48 tracks-per-inch (tpi) and 5876 bits-per-inch (bpi). ''Double density'' (DD or 2D) doubles capacity over SD by replacing FM encoding with an improved line code, such as modified frequency modulation (MFM), modified modified frequency modulation (M²FM), FM/MFM or group coded recording (GCR). 5¼-inch media ''SD'' (''1D'') and ''DD'' (''2D'') designations were generally identical to those of 8-inch disks. ''Quad density'' (QD or 4D) doubl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Personal Computer/AT
The IBM Personal Computer/AT (model 5170, abbreviated as IBM AT or PC/AT) was released in 1984 as the fourth model in the IBM Personal Computer line, following the IBM PC/XT and its IBM Portable PC variant. It was designed around the Intel 80286 microprocessor. Name IBM did not specify an expanded form of "AT" on the machine, press releases, brochures or documentation, but some sources expand the term as "Advanced Technology", including at least one internal IBM document. History IBM's 1984 introduction of the AT was seen as an unusual move for the company, which typically waited for competitors to release new products before producing its own models. At $4,000–6,000, it was only slightly more expensive than considerably slower IBM models. The announcement surprised rival executives, who admitted that matching IBM's prices would be difficult. No major competitor showed a comparable computer at COMDEX Las Vegas that year. Features The AT is IBM PC compatible, with the mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Manchester Encoding
Differential Manchester encoding (DM) is a line code in digital frequency modulation in which data and clock signals are combined to form a single two-level self- synchronizing data stream. In various specific applications, this method is also called by various other names, including biphase mark code (CC), F2F (frequency/double frequency), Aiken biphase, and conditioned diphase.US DoD: ''Design handbook for fiber optic communications systems, Military handbook.'' Dept. of Defense, 1985, p. 65. Definition Differential Manchester encoding is a differential encoding technology, using the presence or absence of transitions to indicate logical value. An improvement to Manchester coding which is a special case of binary phase-shift keying, it is not necessary to know the initial polarity of the transmitted message signal, because the information is not represented by the absolute voltage levels but by their transitions. Differential Manchester encoding has the following advantag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floppy Disk Format
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 -inch disk, using an IBM PC compatible format of 1440 KB, as the only remaining popular format. Different floppy disk types had different recording characteristics, with varying magnetic coercivity (measured in oersteds, or in modern SI units in amperes per meter), ferrite grain size, and tracks per inch (TPI). TPI was not a part of the physical manufacturing process; it was a certification of how closely tracks of data could be spaced on the medium safely. The term density has a double meaning for floppy disks. Originally, single density and double density indicated a difference in logical encoding on the same t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Business
''Canadian Business'' is the longest-publishing business magazine based in Toronto, Ontario, Canada, and founded in 1927. The print edition terminated in the end of 2016. Beginning in January 2017, the magazine was published online only. In October 2021, ''Canadian Business'' relaunched its print edition as a quarterly magazine. History and profile The magazine was founded in 1927. The first issue appeared in February 1928 as ''The Commerce of the Nation'', the organ of the Canadian Chamber of Commerce. The magazine was renamed ''Canadian Business'' in 1933. Canadian Business official association with the Chamber of Commerce ended in 1977, the position of official media partner is currently held by George Media's ''The Canadian Business Journal''. It is owned by Rogers Communications. The company acquired the magazine in 1944. The former owner was Maclean Hunter. ''Canadian Business'' is published every second week, monthly in January, July and August. Its special annual issues i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burroughs Corporation
The Burroughs Corporation was a major American manufacturer of business equipment. The company was founded in 1886 as the American Arithmometer Company. In 1986, it merged with Sperry UNIVAC to form Unisys. The company's history paralleled many of the major developments in computing. At its start, it produced mechanical adding machines, and later moved into programmable ledgers and then computers. It was one of the largest producers of mainframe computers in the world, also producing related equipment including typewriters and printers. Early history In 1886, the American Arithmometer Company was established in St. Louis, Missouri, to produce and sell an adding machine invented by William Seward Burroughs (grandfather of Beat Generation author William S. Burroughs). In 1904, six years after Burroughs' death, the company moved to Detroit and changed its name to the Burroughs Adding Machine Company. It was soon the biggest adding machine company in America. Evolving product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
