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Onyx Computer
Onyx Systems, Inc. was a computer hardware and software company founded in Cupertino, California in 1979 by Bob Marsh and Kip Myers, former managers in Zilog's systems group. It was one of the earliest vendors of microprocessor-based Unix systems. Peter H. Salus, "The Daemon, the GNU and the Penguin/ref> Products The company's first product, the C8000, was a Zilog Zilog Z80, Z80-based micro running the CP/M OS, with a hard disk, and a tape drive for backups. It included IBM terminal emulation and a COBOL compiler, with a Z8000-based CPU add-in board to follow. Later known as the C8001, thus establishing the broader notion of the C8000 series of products, the Z80-based product could be equipped with up to four 64 KB RAM cards for a total of 256 KB. The machine was designed to be upgraded to the subsequent 16-bit model in the range, the C8002, by adding a Z8000 processor card to supplement the existing Z80 card, and for an additional 256 KB of RAM to be added on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corvus Systems
Corvus Systems was a computer technology company that offered, at various points in its history, computer hardware, software, and complete PC systems. History ''Corvus'' was founded by Michael D'Addio and Mark Hahn in 1979. This San Jose, Silicon Valley company pioneered in the early days of personal computers, producing the first hard disk 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 hard disk drive platter, pla ... drives, data backup, and Computer network, networking devices, commonly for the Apple II. The combination of disk storage, backup, and networking was very popular in Primary education, primary and secondary education. A classroom would have a single drive and backup with a full classroom of Apple II computers networked together. Students would log in each time they use the computer and acces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Labs
Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. As a former subsidiary of the American Telephone and Telegraph Company (AT&T), Bell Labs and its researchers have been credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B (programming language), B, C (programming language), C, C++, S (programming language), S, SNOBOL, AWK, AMPL, and others, throughout the 20th century. Eleven Nobel Prizes and five Turing Awards have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telepho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Server
A terminal server connects devices with a serial port to a local area network (LAN). Products marketed as terminal servers can be very simple devices that do not offer any security functionality, such as data encryption and user authentication. The primary application scenario is to enable serial devices to access network server applications, or vice versa, where security of the data on the LAN is not generally an issue. There are also many terminal servers on the market that have highly advanced security functionality to ensure that only qualified personnel can access various servers and that any data that is transmitted across the LAN, or over the Internet, is encrypted. Usually, companies that need a terminal server with these advanced functions want to remotely control, monitor, diagnose and troubleshoot equipment over a telecommunications network. A console server (also referred to as console access server, console management server, serial concentrator, or serial console ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tape Drive
A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic-tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and long archival stability. A tape drive provides sequential access storage, unlike a hard disk drive, which provides direct access storage. A disk drive can move to any position on the disk in a few milliseconds, but a tape drive must physically wind tape between reels to read any one particular piece of data. As a result, tape drives have very large average access times. However, tape drives can stream data very quickly off a tape when the required position has been reached. For example, Linear Tape-Open (LTO) supports continuous data transfer rates of up to 360 MB/s, a rate comparable to hard disk drives. Design Magnetic-tape drives with capacities of less than one megabyte were first used for data storage on mainframe computers in the 1950s. , capac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Computer World
''Personal Computer World'' (''PCW'') (February 1978 - June 2009) was the first British computer magazine. Although for at least the last decade it contained a high proportion of Windows PC content (reflecting the state of the IT field), the magazine's title was not intended as a specific reference to this. At its inception in 1978 'personal computer' was still a generic term (the Apple II, Commodore PET, PET 2001 and TRS-80 had been launched as personal computers in 1977.) The magazine came out before the Wintel (or IBM PC compatible) platform existed; the original IBM PC itself was introduced in 1981. Similarly, the magazine was unrelated to the Amstrad PCW. History ''PCW'' was founded by the Croatian-born Angelo Zgorelec"About the authors" visit-croatia.co.uk. Article retrieved 2006-11-24. in 1978, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Memory Access
Direct memory access (DMA) is a feature of computer systems that allows certain hardware subsystems to access main system computer memory, memory independently of the central processing unit (CPU). Without DMA, when the CPU is using programmed input/output, it is typically fully occupied for the entire duration of the read or write operation, and is thus unavailable to perform other work. With DMA, the CPU first initiates the transfer, then it does other operations while the transfer is in progress, and it finally receives an interrupt from the DMA controller (DMAC) when the operation is done. This feature is useful at any time that the CPU cannot keep up with the rate of data transfer, or when the CPU needs to perform work while waiting for a relatively slow I/O data transfer. Many hardware systems use DMA, including disk drive controllers, graphics cards, network cards and sound cards. DMA is also used for intra-chip data transfer in some multi-core processors. Computers that h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Sector
In computer disk storage, a sector is a subdivision of a track on a magnetic disk or optical disc. For most disks, each sector stores a fixed amount of user-accessible data, traditionally 512 bytes for hard disk drives (HDDs), and 2048 bytes for CD-ROMs, DVD-ROMs and BD-ROMs. Newer HDDs and SSDs use 4096 byte (4 KiB) sectors, which are known as the Advanced Format (AF). The sector is the minimum storage unit of a hard drive. Most disk partitioning schemes are designed to have files occupy an integral number of sectors regardless of the file's actual size. Files that do not fill a whole sector will have the remainder of their last sector filled with zeroes. In practice, operating systems typically operate on blocks of data, which may span multiple sectors. Geometrically, the word sector means a portion of a disk between a center, two radii and a corresponding arc (see Figure 1, item B), which is shaped like a slice of a pie. Thus, the ''disk sector'' (Figure 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floating-point Unit
A floating-point unit (FPU), numeric processing unit (NPU), colloquially math coprocessor, is a part of a computer system specially designed to carry out operations on floating-point numbers. Typical operations are addition, subtraction, multiplication, division, and square root. Modern designs generally include a fused multiply-add instruction, which was found to be very common in real-world code. Some FPUs can also perform various transcendental functions such as exponential or trigonometric calculations, but the accuracy can be low, so some systems prefer to compute these functions in software. Floating-point operations were originally handled in software in early computers. Over time, manufacturers began to provide standardized floating-point libraries as part of their software collections. Some machines, those dedicated to scientific processing, would include specialized hardware to perform some of these tasks with much greater speed. The introduction of microcode in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Am9511/9512
The Intel 8231 and 8232 were early designs of floating-point maths coprocessors (FPUs), marketed for use with their i8080 line of primary CPUs. They were licensed versions of AMD's Am9511 and Am9512 FPUs, from 1977 and 1979, themselves claimed by AMD as the world's first single-chip FPU solutions. Adoption Whilst the i8231/i8232 (and their AMD-branded cousins) were primarily intended to partner the i8080 (or the AMD clone Am9080), the multiple interface options in their design, from simple wait state insertion and status polling routines to interrupt and DMA controller driven methods suitable for a peripheral processor or add-in board, meant that – with a small amount of glue logic – it was usable in almost any microprocessor system that had a DMA subsystem or a spare interrupt input/interrupt vector available, and AMD's original documentation provided several different examples. This was a valuable feature for one of the first commercially available single-chip FPUs, gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minicomputer
A minicomputer, or colloquially mini, is a type of general-purpose computer mostly developed from the mid-1960s, built significantly smaller and sold at a much lower price than mainframe computers . By 21st century-standards however, a mini is an exceptionally large machine. Minicomputers in the traditional technical sense covered here are only small relative to generally even earlier and much bigger machines. The class formed a distinct group with its own software architectures and operating systems. Minis were designed for control, instrumentation, human interaction, and communication switching, as distinct from calculation and record keeping. Many were sold indirectly to original equipment manufacturers (OEMs) for final end-use application. During the two-decade lifetime of the minicomputer class (1965–1985), almost 100 minicomputer vendor companies formed. Only a half-dozen remained by the mid-1980s. When single-chip CPU microprocessors appeared in the 1970s, the defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Page (computer Memory)
A page, memory page, or virtual page is a fixed-length contiguous block of virtual memory, described by a single entry in a page table. It is the smallest unit of data for memory management in an operating system that uses virtual memory. Similarly, a page frame is the smallest fixed-length contiguous block of physical memory into which memory pages are mapped by the operating system. A transfer of pages between main memory and an auxiliary store, such as a hard disk drive, is referred to as paging or swapping. Explanation Computer memory is divided into pages so that information can be found more quickly. The concept is named by analogy to the pages of a printed book. If a reader wanted to find, for example, the 5,000th word in the book, they could count from the first word. This would be time-consuming. It would be much faster if the reader had a listing of how many words are on each page. From this listing they could determine which page the 5,000th word appears on, and h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
