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Apple PC 5.25 Drive
The Disk II Floppy Disk Subsystem, often rendered as Disk ] '', is a -inch floppy disk drive designed by Apple II (original)">Apple II Apple II ("apple Roman numerals, two", stylized as Apple ) is a series of microcomputers manufactured by Apple Computer, Inc. from 1977 to 1993. The Apple II (original), original Apple II model, which gave the series its name, was designed ... personal computer A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ... to replace the slower cassette tape The Compact Cassette, also commonly called a cassette tape, audio cassette, or simply tape or cassette, is an analog audio, analog magnetic tape recording format for Sound recording and reproduction, audio recording and playback. Invented by L ... storage. Apple produced at least six variant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shugart Associates
Shugart Associates (later Shugart Corporation) was a computer peripheral manufacturer that dominated the floppy disk drive market in the late 1970s and is famous for introducing the -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. Founded in 1973, Shugart Associates was purchased in 1977 by Xerox, which then exited the business in 1985 and 1986, selling the brand name and the 8-inch floppy product line (in March 1986) to Narlinger Group, which ultimately ceased operations circa 1991. History Beginnings After a distinguished career at IBM and a few years at Memorex, Alan Shugart decided to strike out on his own in 1973. After gathering venture capital, he started Shugart Associates. The original business plan was to build a small-business system (similar to the IBM 3740) dealing with the developm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PC Magazine
''PC Magazine'' (shortened as ''PCMag'') is an American computer magazine published by Ziff Davis. A print edition was published from 1982 to January 2009. Publication of online editions started in late 1994 and continues . Overview ''PC Magazine'' provides reviews and previews of the latest hardware and software for the information technology professional. Other regular departments include columns by long-time editor-in-chief Michael J. Miller ("Forward Thinking"), Bill Machrone, and Jim Louderback, as well as: * "First Looks" (a collection of reviews of newly released products) * "Pipeline" (a collection of short articles and snippets on computer-industry developments) * "Solutions" (which includes various how-to articles) * "User-to-User" (a section in which the magazine's experts answer user-submitted questions) * "After Hours" (a section about various computer entertainment products; the designation "After Hours" is a legacy of the magazine's traditional orientation to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRS-80 Model I
The TRS-80 Micro Computer System (TRS-80, later renamed the Model I to distinguish it from successors) is a desktop microcomputer developed by American company Tandy Corporation and sold through their Radio Shack stores. Launched in 1977, it is one of the earliest mass-produced and mass-marketed retail home computers. The name is an abbreviation of ''Tandy Radio Shack, Z80 icroprocessor', referring to its Zilog Z80 8-bit microprocessor. The TRS-80 has a full-stroke QWERTY keyboard, 4 KB dynamic random-access memory (DRAM) standard memory, small size and desk area, floating-point Level I BASIC language interpreter in read-only memory (ROM), 64-character-per-line video monitor, and had a starting price of US$600 (equivalent to US$ in ). A cassette tape drive for program storage was included in the original package. While the software environment was stable, the cassette load/save process combined with keyboard bounce issues and a troublesome Expansion Interface contributed to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VisiCalc
VisiCalc ("visible calculator") is the first spreadsheet computer program for personal computers, originally released for the Apple II by VisiCorp on October 17, 1979. It is considered the killer application for the Apple II, turning the microcomputer from a hobby for computer enthusiasts into a serious business tool, and then prompting IBM to introduce the IBM PC two years later. More than 700,000 copies were sold in six years, and up to 1 million copies over its history. Initially developed for the Apple II computer using a 6502 assembler running on the Multics time-sharing system, VisiCalc was ported to numerous platforms, both 8-bit and some of the early 16-bit systems. To do this, the company developed porting platforms that produced bug compatible versions. The company took the same approach when the IBM PC was launched, producing a product that was essentially identical to the original 8-bit Apple II version. Sales were initially brisk, with about 300,000 copies sold. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Frequency Modulation
In telecommunications, a line code is a pattern of voltage, current, or photons used to represent digital data transmitted down a communication channel or written to a storage medium. This repertoire of signals is usually called a constrained code in data storage systems. Some signals are more prone to error than others as the physics of the communication channel or storage medium constrains the repertoire of signals that can be used reliably. Common line encodings are unipolar, polar, bipolar, and Manchester code. Transmission and storage After line coding, the signal is put through a physical communication channel, either a transmission medium or data storage medium.Karl Paulsen"Coding for Magnetic Storage Mediums".2007. The most common physical channels are: * the line-coded signal can directly be put on a transmission line, in the form of variations of the voltage or current (often using differential signaling). * the line-coded signal (the ''baseband signal'') under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soft-sectored
Floppy disk format and density refer to the physical and logical layout of data stored on a floppy disk. Since their introduction, there have been many floppy disk types, densities, and formats, popular and rare, 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 KiB, as the only remaining popular format. Different floppy disk types have 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Star Computers
North Star Computers Inc. (later styled as NorthStar) was an American computer company based in Berkeley, California existing between June 1976 and 1989. Originally a mail order business for IMS Associates, Inc., IMSAI computers, it soon developed into a major player in the early microcomputer market, becoming first known for their low-cost floppy disk system for S-100 bus machines, and later for their own S-100 bus computers running either the CP/M, CP/M operating system or North Star's own proprietary operating system, NSDOS. North Star BASIC was a common dialect of the popular BASIC programming language. They later expanded their lineup with dual-CPU machines able to run MS-DOS, and a server version running either DOS or Novell NetWare. While initially successful, North Star's sales suffered from the company's adherence to hard sector floppy drives which made software difficult to port onto North Star machines. It was no longer a significant factor in the industry by the time le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solenoid
upright=1.20, An illustration of a solenoid upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose length is substantially greater than its diameter, which generates a controlled magnetic field. The coil can produce a uniform magnetic field in a volume of space when an electric current is passed through it. André-Marie Ampère coined the term ''solenoid'' in 1823, having conceived of the device in 1820. The French term originally created by Ampère is ''solénoïde'', which is a French transliteration of the Greek word '' σωληνοειδὴς'' which means ''tubular''. The helical coil of a solenoid does not necessarily need to revolve around a straight-line axis; for example, William Sturgeon's electromagnet of 1824 consisted of a solenoid bent into a horseshoe shape (similarly to an arc spring). Solenoids provide magnetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steve Jobs
Steven Paul Jobs (February 24, 1955 – October 5, 2011) was an American businessman, inventor, and investor best known for co-founding the technology company Apple Inc. Jobs was also the founder of NeXT and chairman and majority shareholder of Pixar. He was a pioneer of the personal computer revolution of the 1970s and 1980s, along with his early business partner and fellow Apple co-founder Steve Wozniak. Jobs was born in San Francisco in 1955 and adopted shortly afterwards. He attended Reed College in 1972 before withdrawing that same year. In 1974, he traveled through India, Hippie trail, seeking enlightenment before later studying Buddhism in the West#Emerging mainstream western Buddhism, Zen Buddhism. He and Wozniak co-founded Apple in 1976 to further develop and sell Wozniak's Apple I personal computer. Together, the duo gained fame and wealth a year later with production and sale of the Apple II, one of the first highly successful mass-produced microcomputers. Jobs saw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
