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Typeahead
Typeahead is a feature of computers and software (and some typewriters) that enables users to continue typing regardless of program or computer operation—the user may type in whatever speed is desired, and if the receiving software is busy at the time it will be called to handle this later. Often this means that keystrokes entered will not be displayed on the screen immediately. This programming technique for handling uses what is known as a keyboard buffer. Typeahead has its roots in the age of typewriters. The IBM Selectric typewriter, first released in 1961, had a mechanical key lockout feature designed to smooth out typists' irregular keystrokes that, to many users, felt like typeahead. Achieving true typeahead requires maintaining a so-called "typeahead buffer"—a FIFO queue, for instance—whose role it is to store a limited amount of keyboard input until it is called for. Installing such a buffer can be done at both the hardware and the software levels; most modern op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interrupt
In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, the processor will suspend its current activities, save its state, and execute a function called an '' interrupt handler'' (or an ''interrupt service routine'', ISR) to deal with the event. This interruption is often temporary, allowing the software to resume normal activities after the interrupt handler finishes, although the interrupt could instead indicate a fatal error. Interrupts are commonly used by hardware devices to indicate electronic or physical state changes that require time-sensitive attention. Interrupts are also commonly used to implement computer multitasking and system calls, especially in real-time computing. Systems that use interrupts in these ways are said to be interrupt-driven. History Hardware interrupts wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyboard Buffer
A keyboard buffer is a section of computer computer storage, memory used to hold keystrokes before they are processed. Computer keyboard, Keyboard buffers have long been used in command line interface, command-line processing. As a user enters a command, they see it Echo (computing), echoed on their computer display, terminal and can edit it before it is processed by the computer. In time-sharing systems, the location of the buffer depends on whether communications is full-Duplex (telecommunications), duplex or half-duplex. In full-duplex systems, keystrokes are transmitted one by one. As the main computer receives each keystroke, it ordinarily appends the character which it represents to the end of the keyboard buffer. The exception is control characters, such as "delete" or "backspace" which correct typing mistakes by deleting the character at the end of the buffer. In half-duplex systems, keystrokes are echoed locally on a computer terminal. The user can see the command line o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer
A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic sets of operations known as Computer program, ''programs'', which enable computers to perform a wide range of tasks. The term computer system may refer to a nominally complete computer that includes the Computer hardware, hardware, operating system, software, and peripheral equipment needed and used for full operation; or to a group of computers that are linked and function together, such as a computer network or computer cluster. A broad range of Programmable logic controller, industrial and Consumer electronics, consumer products use computers as control systems, including simple special-purpose devices like microwave ovens and remote controls, and factory devices like industrial robots. Computers are at the core of general-purpose devices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software
Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital computers in the mid-20th century. Early programs were written in the machine language specific to the hardware. The introduction of high-level programming languages in 1958 allowed for more human-readable instructions, making software development easier and more portable across different computer architectures. Software in a programming language is run through a compiler or Interpreter (computing), interpreter to execution (computing), execute on the architecture's hardware. Over time, software has become complex, owing to developments in Computer network, networking, operating systems, and databases. Software can generally be categorized into two main types: # operating systems, which manage hardware resources and provide services for applicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typewriter
A typewriter is a Machine, mechanical or electromechanical machine for typing characters. Typically, a typewriter has an array of Button (control), keys, and each one causes a different single character to be produced on paper by striking an ink ribbon, inked ribbon selectively against the paper with a Sort (typesetting), type element. Thereby, the machine produces a legible written document composed of ink and paper. By the end of the 19th century, a ''person'' who used such a device was also referred to as a ''typewriter''. The first commercial typewriters were introduced in 1874, but did not become common in offices in the United States until after the mid-1880s. The typewriter quickly became an indispensable tool for practically all writing other than personal handwritten correspondence. It was widely used by professional writers, in offices, in business correspondence in private homes, and by students preparing written assignments. Typewriters were a standard fixture in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Selectric Typewriter
The IBM Selectric (a portmanteau of "selective" and "electric") was a highly successful line of electric typewriters introduced by IBM on 31 July 1961. Instead of the "basket" of individual typebars that swung up to strike the ribbon and page in a typical typewriter of the period, the Selectric had a chrome-plated plastic "element" (frequently called a "typeball", or less formally, a "golf ball") that rotated and tilted to the correct position before striking the paper. The element could be easily interchanged to use different fonts within the same document typed on the same typewriter, resurrecting a capability which had been pioneered by typewriters such as the Hammond and Blickensderfer in the late 19th century. The Selectric also replaced the traditional typewriter's horizontally moving carriage with a roller (platen) that turned to advance the paper vertically while the typeball and ribbon mechanism moved horizontally across the paper. The Selectric mechanism was notable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Buffer
In computer science, a data buffer (or just buffer) is a region of memory used to store data temporarily while it is being moved from one place to another. Typically, the data is stored in a buffer as it is retrieved from an input device (such as a microphone) or just before it is sent to an output device (such as speakers); however, a buffer may be used when data is moved between processes within a computer, comparable to buffers in telecommunication. Buffers can be implemented in a fixed memory location in hardware or by using a virtual data buffer in software that points at a location in the physical memory. In all cases, the data stored in a data buffer is stored on a physical storage medium. The majority of buffers are implemented in software, which typically use RAM to store temporary data because of its much faster access time when compared with hard disk drives. Buffers are typically used when there is a difference between the rate at which data is received and the rate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FIFO (computing And Electronics)
Representation of a FIFO queue In computing and in systems theory, first in, first out (the first in is the first out), acronymized as FIFO, is a method for organizing the manipulation of a data structure (often, specifically a data buffer) where the oldest (first) entry, or "head" of the queue, is processed first. Such processing is analogous to servicing people in a queue area on a first-come, first-served (FCFS) basis, i.e. in the same sequence in which they arrive at the queue's tail. FCFS is also the jargon term for the FIFO operating system scheduling algorithm, which gives every process central processing unit (CPU) time in the order in which it is demanded. FIFO's opposite is LIFO, last-in-first-out, where the youngest entry or "top of the stack" is processed first. A priority queue is neither FIFO or LIFO but may adopt similar behaviour temporarily or by default. Queueing theory encompasses these methods for processing data structures, as well as interactions be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Keyboard
A computer keyboard is a built-in or peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or Push-button, keys to act as Mechanical keyboard, mechanical levers or Electronic switching system, electronic switches. Replacing early punched cards and paper tape technology, interaction via teleprinter-style keyboards have been the main input device, input method for computers since the 1970s, supplemented by the computer mouse since the 1980s, and the touchscreen since the 2000s. Keyboard keys (buttons) typically have a set of characters Engraving, engraved or Printing, printed on them, and each press of a key typically corresponds to a single written symbol. However, producing some symbols may require pressing and holding several keys simultaneously or in sequence. While most keys produce character (computing), characters (Letter (alphabet), letters, Numerical digit, numbers or symbols), other keys (such as the escape key) can prompt the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley ( BSD), Microsoft (Xenix), Sun Microsystems ( SunOS/ Solaris), HP/ HPE ( HP-UX), and IBM ( AIX). The early versions of Unix—which are retrospectively referred to as " Research Unix"—ran on computers such as the PDP-11 and VAX; Unix was commonly used on minicomputers and mainframes from the 1970s onwards. It distinguished itself from its predecessors as the first portable operating system: almost the entire operating system is written in the C programming language (in 1973), which allows U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel (operating System)
A kernel is a computer program at the core of a computer's operating system that always has complete control over everything in the system. The kernel is also responsible for preventing and mitigating conflicts between different processes. It is the portion of the operating system code that is always resident in memory and facilitates interactions between hardware and software components. A full kernel controls all hardware resources (e.g. I/O, memory, cryptography) via device drivers, arbitrates conflicts between processes concerning such resources, and optimizes the use of common resources, such as CPU, cache, file systems, and network sockets. On most systems, the kernel is one of the first programs loaded on startup (after the bootloader). It handles the rest of startup as well as memory, peripherals, and input/output (I/O) requests from software, translating them into data-processing instructions for the central processing unit. The critical code of the kernel is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Network
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or by wireless communication. The devices may be connected in a variety of network topologies. In order to communicate over the network, computers use agreed-on rules, called communication protocols, over whatever medium is used. The computer network can include personal computers, Server (computing), servers, networking hardware, or other specialized or general-purpose Host (network), hosts. They are identified by network addresses and may have hostnames. Hostnames serve as memorable labels for the nodes and are rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
