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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] |
List Of Floppy Disk Formats
This is a list of different floppy disk formats. IBM 8-inch formats This is a list of 8-inch floppy diskette formats as introduced by IBM. DEC 8-inch formats Digital Equipment Corporation used the following formats on 8-inch disks: Other manufacturers Physical composition Logical formats Throughout the 1970s and 1980s, many different logical disk formats were used, depending on the hardware platform. Ref. https://www.trs-80.com/wordpress/trs-80-computer-line/model-i/ https://www.trs-80.com/wordpress/trs-80-computer-line/model-ii/ https://www.trs-80.com/wordpress/trs-80-computer-line/model-4/ See also * Zip drive (floppy-like, but incompatible medium using different technology) * PocketZip (floppy-like, but incompatible medium using different technology) * SuperDisk The SuperDisk LS-120 is a high-speed, high-capacity alternative to the 90 mm (3.5 in), 1.44 MB floppy disk. The SuperDisk hardware was created by 3M's storage products ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floppy Disk
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 disk ... [...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] |
Magnetic Storage
Magnetic 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 disk read-and-write head, read/write heads. Magnetic storage media, primarily Hard disk drive, hard disks, are widely used to store Data (computing), computer data as well as sound, audio and video signals. In the field of computing, the term ''magnetic storage'' is preferred and in the field of audio and video production, the term ''magnetic recording'' is more commonly used. The distinction is less technical and more a matter of preference. Other examples of magnetic storage media include floppy disks, magnetic tape, and magnetic stripe card, magnetic stripes on credit cards. History Magnetic storage in the form of wire recording—audio recording on a wire—was publicized by Oberlin Smith in the Sept 8, 1888 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel Corporation
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 series of instruction sets, the instruction sets found in most personal computers (PCs). Incorporated in Delaware, Intel ranked No. 45 in the 2020 ''Fortune'' 500 list of the largest United States corporations by total revenue for nearly a decade, from 2007 to 2016 fiscal years. Intel supplies microprocessors for computer system manufacturers such as Acer, Lenovo, HP, and Dell. Intel also manufactures motherboard chipsets, network interface controllers and integrated circuits, flash memory, graphics chips, embedded processors and other devices related to communications and computing. Intel (''int''egrated and ''el''ectronics) was founded on July 18, 1968, by semiconductor pioneers Gordon Moore (of Moore's law) and Robert Noyce (1927–19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PC88VA3
The , commonly shortened to PC-88, are a brand of Zilog Z80-based 8-bit home computers released by Nippon Electric Company (NEC) in 1981 and primarily sold in Japan. The PC-8800 series sold extremely well and became one of the three major Japanese home computers of the 1980s, along with the Fujitsu FM-7 and Sharp X1. It was later eclipsed by NEC's 16-bit PC-9800 series, although it still maintained strong sales up until the early 90s. NEC's American subsidiary, NEC Home Electronics (USA), marketed variations of the PC-8800 in the United States and Canada. History Nippon Electric's Microcomputer Sales Section of the Electronic Device Sales Division launched the PC-8001 in September 1979, and by 1981 it consisted of 40% of the Japanese personal computer market. In April 1981, Nippon Electric decided to expand personal computer lines into three groups: New Nippon Electric, Information Processing Group and Electronic Devices Group, with each specializing in a particular serie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hitachi-Maxell
, commonly known as Maxell, is a Japanese company that manufactures consumer electronics. The company's name is a contraction of "Maximum capacity dry cell". Its main products are batteries, wireless charging products, storage devices, LCD/laser projectors, and functional materials. In the past, the company manufactured recording media, including audio cassettes and blank VHS tapes, floppy disks, and recordable optical discs including CD-R/RW and DVD±RW. On March 4, 2008, Maxell announced that they would outsource the manufacturing of their optical media. History Maxell was formed in 1960, when a dry cell manufacturing plant was created at the company's headquarters in Ibaraki, Osaka. In 1961, Maxell Electric Industrial Company, Limited was created out of the dry battery and magnetic tape divisions of Nitto Electric Industrial Company, Limited (now Nitto Denko Corporation). On March 18, 2014, the company was listed on the First Section of the Tokyo Stock Exchange. In 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computerwoche
''Computerworld'' (abbreviated as CW) is an ongoing decades old professional publication which in 2014 "went digital." Its audience is information technology (IT) and business technology professionals, and is available via a publication website and as a digital magazine. As a printed weekly during the 1970s and into the 1980s, ''Computerworld'' was the leading trade publication in the data processing industry. Indeed, based on circulation and revenue it was one of the most successful trade publications in any industry. Later in the 1980s it began to lose its dominant position. It is published in many countries around the world under the same or similar names. Each country's version of ''Computerworld'' includes original content and is managed independently. The parent company of Computerworld US is IDG Communications. History The first issue was published in 1967. Going international The company IDG offers the brand "Computerworld" in 47 countries worldwide, the name and fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NEC Corporation
is a Japanese multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It provides IT and network solutions, including cloud computing, artificial intelligence (AI), Internet of things (IoT) platform, and telecommunications equipment and software to business enterprises, communications services providers and to government agencies, and has also been the biggest PC vendor in Japan since the 1980s when it launched the PC-8000 series. NEC was the world's fourth-largest PC manufacturer by 1990. Its semiconductors business unit was the world's largest semiconductor company by annual revenue from 1985 to 1992, the second largest in 1995, one of the top three in 2000, and one of the top 10 in 2006. NEC spun off its semiconductor business to Renesas Electronics and Elpida Memory. Once Japan's major electronics company, NEC has largely withdrawn from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epson PX-8
The Epson PX-8 a.k.a. Geneva was a small laptop computer made by the Epson Corporation in the mid-1980s. It had a Z80 compatible microprocessor, and ran a customized version of the CP/M-80 operating system as well as various applications from a pair of ROM cartridge slots which were treated as drives. For file storage, it had a built-in microcassette drive. The PX-8 did not have an internal disk drive, and instead allowed either memory to be partitioned into application memory and a RAM disk, or an external 60 KB or 120 KB intelligent RAM disk module to be attached (64K and 128K internally but some used for the processor). The intelligent RAM disk module had its own Z80 processor with a backup battery. The PX-8 had an 80 column by 8 line LCD display, which was monochromatic and non-backlit. It used an internal nickel-cadmium battery, and had a battery life in the range of 6–8 hours when using word-processing software. An additional battery provided backup for the internal RA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epson PF-10
The Epson PX-8 a.k.a. Geneva was a small laptop computer made by the Epson Corporation in the mid-1980s. It had a Z80 compatible microprocessor, and ran a customized version of the CP/M-80 operating system as well as various applications from a pair of ROM cartridge slots which were treated as drives. For file storage, it had a built-in microcassette drive. The PX-8 did not have an internal disk drive, and instead allowed either memory to be partitioned into application memory and a RAM disk, or an external 60 KB or 120 KB intelligent RAM disk module to be attached (64K and 128K internally but some used for the processor). The intelligent RAM disk module had its own Z80 processor with a backup battery. The PX-8 had an 80 column by 8 line LCD display, which was monochromatic and non-backlit. It used an internal nickel-cadmium battery, and had a battery life in the range of 6–8 hours when using word-processing software. An additional battery provided backup for the internal RA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epson Corporation
Seiko Epson Corporation, or simply known as Epson, is a Japanese multinational electronics company and one of the world's largest manufacturers of computer printers and information- and imaging-related equipment. Headquartered in Suwa, Nagano, Japan, the company has numerous subsidiaries worldwide and manufactures inkjet, dot matrix, thermal and laser printers for consumer, business and industrial use, scanners, laptop and desktop computers, video projectors, watches, point of sale systems, robots and industrial automation equipment, semiconductor devices, crystal oscillators, sensing systems and other associated electronic components. The company has developed as one of manufacturing and research & development companies (formerly known as Seikosha) of the former Seiko Group, a name traditionally known for manufacturing Seiko timepieces since its founding. Seiko Epson was one of the major companies in the Seiko Group, but is neither a subsidiary nor an affiliate o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
