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Psion Organiser
Psion Organiser was the brand name of a range of pocket computers developed by the British company Psion in the 1980s. The Organiser I (launched in 1984) and Organiser II (launched in 1986) had a characteristic hard plastic sliding cover protecting a 6×6 keypad instead of a computer keyboard, with letters arranged alphabetically. The Organiser II competed with the Filofax and can be considered the first usable electronic organizer or personal digital assistant (PDA) in that it combined an electronic diary and searchable address database in a small, portable device. Production of consumer hand-held devices by Psion has now ceased; the company, after corporate changes, now concentrates on hardware and software for industrial and commercial data-collection applications. On an episode of ''The Gadget Show'', first aired 30 March 2009, the Psion was pitted against the BlackBerry for a place on the show's Hall of Fame. Whilst the Psion was highly praised as a device that pioneere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pocket Computer
A pocket computer is a class of handheld computer characterized by very short displays (typically accommodating only one or a handful of lines of text) and calculator-style alphanumeric keypads. Pocket computers occupy a small footprint, allowing the unit to be comfortably stashed in one's pocket when on the go, and usually weigh less than . Many feature a port for an expansion chassis, allowing the computers to be used with external peripherals. Pocket computers had their peak of popularity in the early 1980s, but sales quickly plateaued and declined in Western markets as consumers became aware of their limitations. In Japan, where they were invented, pocket computers maintained their popularity and continued to be used as teaching aids into the 21st century. History The first pocket computer was the Sharp PC-1211, introduced in March 1980 by Sharp Corporation and sold exclusively in Japan. Later in 1980, the PC-1211 was resold and rebranded by Tandy Corporation in the Unite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Dollar
The Canadian dollar (currency symbol, symbol: $; ISO 4217, code: CAD; ) is the currency of Canada. It is abbreviated with the dollar sign $. There is no standard disambiguating form, but the abbreviations Can$, CA$ and C$ are frequently used for distinction from other dollar-denominated currencies (though C$ remains ambiguous with the Nicaraguan córdoba). It is divided into 100 cent (currency), cents (¢). Owing to the image of a common loon on its reverse, the dollar coin, and sometimes the unit of currency itself, may be metonymy, referred to as the ''loonie'' by English-speaking Canadians and foreign exchange traders and analysts. Accounting for approximately two per cent of all global reserves, the Canadian dollar is the fifth-most held reserve currency in the world, behind the United States dollar, US dollar, euro, Japanese yen, yen, and pound sterling, sterling. The Canadian dollar is popular with central banks because of Canada's relative economic soundness, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Write Once Read Many
Write once read many (WORM) describes a data storage device in which information, once written, cannot be modified. This write protection affords the assurance that the data cannot be tampered with once it is written to the device, excluding the possibility of data loss from human error, computer bugs, or malware. On ordinary (non-WORM) data storage devices, the number of times data can be modified is limited only by the lifespan of the device, as modification involves physical changes that may cause wear to the device. The "read many" aspect is unremarkable, as modern storage devices permit unlimited reading of data once written. Historical exceptions include time-limited discs such as Flexplay, designed for short-term rental of movies; and early non-volatile memory technologies such as magnetic-core memory and bubble memory, from which reading data also erased it. WORM prevents important data being deleted or modified, helping to preserve its authenticity. History WORM dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, peripherals, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computerfrom cellular phones and video game consoles to web servers and supercomputers. , Android (operating system), Android is the most popular operating system with a 46% market share, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calculator
An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics. The first solid-state electronic calculator was created in the early 1960s. Pocket-sized devices became available in the 1970s, especially after the Intel 4004, the first microprocessor, was developed by Intel for the Japanese calculator company Busicom. Modern electronic calculators vary from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in the mid-1970s as the incorporation of integrated circuits reduced their size and cost. By the end of that decade, prices had dropped to the point where a basic calculator was affordable to most and they became common in schools. In addition to general-purpose calculators, there are those designed for specific markets. For example, there are scientific calculators, which include trigonometric and statistical calculat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flat-file Database
A flat-file database is a database stored in a file called a flat file. Records follow a uniform format, and there are no structures for indexing or recognizing relationships between records. The file is simple. A flat file can be a plain text file (e.g. csv, txt or tsv), or a binary file. Relationships can be inferred from the data in the database, but the database format itself does not make those relationships explicit. The term has generally implied a small database, but very large databases can also be flat. Overview Plain text files usually contain one record per line. Examples of flat files include /etc/passwd and /etc/group on Unix-like operating systems. Another example of a flat file is a name-and-address list with the fields ''Name'', ''Address'' and ''Phone Number''. Flat files are typically either delimiter-separated or fixed-width. Delimiter-separated values In delimiter-separated values files, the fields are separated by a character or string c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Crystal Display
A liquid-crystal display (LCD) is a flat-panel display or other Electro-optic modulator, electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liquid crystals do not emit light directly but instead use a backlight or Reflector (photography), reflector to produce images in color or Monochrome monitor, monochrome. LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images with low information content, which can be displayed or hidden: preset words, digits, and seven-segment displays (as in a digital clock) are all examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs are used in a wide range of applications, including LCD televisions, computer monitors, Dashboard, instrument panels, flight instrument ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Static RAM
Static random-access memory (static RAM or SRAM) is a type of random-access memory (RAM) that uses latching circuitry (flip-flop) to store each bit. SRAM is volatile memory; data is lost when power is removed. The ''static'' qualifier differentiates SRAM from ''dynamic'' random-access memory (DRAM): * SRAM will hold its data permanently in the presence of power, while data in DRAM decays in seconds and thus must be periodically refreshed. * SRAM is faster than DRAM but it is more expensive in terms of silicon area and cost. * Typically, SRAM is used for the cache and internal registers of a CPU while DRAM is used for a computer's main memory. History Semiconductor bipolar SRAM was invented in 1963 by Robert Norman at Fairchild Semiconductor. Metal–oxide–semiconductor SRAM (MOS-SRAM) was invented in 1964 by John Schmidt at Fairchild Semiconductor. The first device was a 64-bit MOS p-channel SRAM. SRAM was the main driver behind any new CMOS-based technology fabrica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Read-only Memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications, such as video games, for programmable devices can be distributed as ROM cartridge, plug-in cartridges containing ROM. Strictly speaking, ''read-only memory'' refers to hard-wired memory, such as diode matrix or a #Solid-state ROM, mask ROM integrated circuit (IC), that cannot be electronically changed after manufacture. Although discrete circuits can be altered in principle, through the addition of Jump wire, bodge wires and the removal or replacement of components, ICs cannot. Correction of errors, or updates to the software, require new devices to be manufactured and to replace the installed device. Floating-gate ROM semiconductor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8-bit
In computer architecture, 8-bit integers or other data units are those that are 8 bits wide (1 octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. Memory addresses (and thus address buses) for 8-bit CPUs are generally larger than 8-bit, usually 16-bit. 8-bit microcomputers are microcomputers that use 8-bit microprocessors. The term '8-bit' is also applied to the character sets that could be used on computers with 8-bit bytes, the best known being various forms of extended ASCII, including the ISO/IEC 8859 series of national character sets especially Latin 1 for English and Western European languages. The IBM System/360 introduced byte-addressable memory with 8-bit bytes, as opposed to bit-addressable or decimal digit-addressable or word-addressable memory, although its general-purpose registers were 32 bits wide, and addresses were contained in the lower 24 bits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keypad
A keypad is a block or pad of buttons set with an arrangement of digits, symbols, or alphabetical letters. Pads mostly containing numbers and used with computers are numeric keypads. Keypads are found on devices which require mainly numeric input such as calculators, television remotes, push-button telephones, vending machines, ATMs, point of sale terminals, combination locks, safes, and digital door locks. Many devices follow the E.161 standard for their arrangement. Uses and functions A computer keyboard usually has a small numeric keypad on the side, in addition to the other number keys on the top, but with a calculator-style arrangement of buttons that allow more efficient entry of numerical data. This number pad (commonly abbreviated to ''numpad'') is usually positioned on the right side of the keyboard because most people are right-handed. Many laptop computers have special function keys that turn part of the alphabetical keyboard into a numerical keypad as there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
