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In computer science, an interrupt is a signal from a device which typically results in a (register) context switch: that is, the processor sets aside what it's doing and does something else. Wikibooks Wikiversity has more about this subject: School of Computer Science Open Directory Project: Computer Science Downloadable Science and Computer Science books Collection of Computer Science Bibliographies Belief that title science in computer science is inappropriate Categories: Wikipedia articles needing priority cleanup | Computer science ...
A context switch is the computing process of storing and restoring the state of a CPU (the context) such that multiple processes can share a single CPU resource. ...
Digital computers usually provide a way to start software routines in response to asynchronous electronic events. These events are signaled to the processor via interrupt requests. The processor and interrupt code make a (register) context switch into a specifically written piece of software to handle the interrupt. This software is called the interrupt service routine, or interrupt handler. The addresses of these handlers are termed interrupt vectors and are generally stored in a table in RAM (the Interrupt Vector Table), allowing them to be modified if required. A computer is a device or machine for processing information from data according to a program — a compiled list of instructions. ...
Asynchrony is the state of not being synchronized. ...
A CPU The exact term processor is a sub-system of a data processing system which processes received information after it has been encoded into data by the input sub-system. ...
A context switch is the computing process of storing and restoring the state of a CPU (the context) such that multiple processes can share a single CPU resource. ...
An Interrupt Handler is the modern progression of an interrupt service routine, a routine whose execution is triggered by an interrupt. ...
Interrupt vector Computing term. ...
This article needs to be cleaned up to conform to a higher standard of quality. ...
Interrupts were originated to avoid wasting the computer's valuable time in software loops (called polling loops) waiting for electronic events. Instead, the computer was able to do other useful work while the event was pending. The interrupt would signal the computer when the event occurred, allowing efficient accommodation for slow mechanical devices.
Interrupts allow modern computers to respond promptly to electronic events, while other work is being performed. Computer architectures also provide instructions to permit processes to initiate software interrupts or traps. These can be used, for instance, to implement co-operative multitasking. In computing, cooperative multitasking (or non-preemptive multitasking) is a form of multitasking in which multiple tasks execute by voluntarily ceding control to other tasks at programmer-defined points within each task. ...
A well-designed interrupt mechanism arranges the design of the computer bus, software and interrupting device so that if some single part of the interrupt sequence fails, the interrupt restarts and runs to completion. Usually there is an electronic request, an electronic response, and a software operation to turn off the device's interrupt, to prevent another request. In computer architecture, a bus is a subsystem that transfers data or power between computer components inside a computer or between computers. ...
Interrupt types Typical interrupt types include: - timer interrupts
- disk interrupts
- power-off interrupts
- traps
Other interrupts exist to transfer data bytes using UARTs, or Ethernet, sense key-presses, control motors, or anything else the equipment must do. A UART or universal asynchronous receiver-transmitter is a piece of computer hardware that translates between parallel bits of data and serial bits. ...
Ethernet is a frame-based computer networking technology for local area networks (LANs). ...
A classic timer interrupt just interrupts periodically from a counter or the power-line. The software (usually part of an operating system) counts the interrupts to keep time. The timer interrupt may also be used to reschedule the priorities of running processes. Counters are popular, but some older computers used the power line frequency instead, because power companies in most Western countries control the power-line frequency with an atomic clock. In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ...
Process (lat. ...
Atomic clock Chip-Scale Atomic Clock Unveiled by NIST An atomic clock is a type of clock that uses an atomic resonance frequency standard as its counter. ...
A disk interrupt signals the completion of a data transfer from or to the disk peripheral. A process waiting to read or write a file starts up again.
A power-off interrupt predicts or requests a loss of power. It allows the computer equipment to perform an orderly shutdown.
Interrupts are also used in typeahead features for buffering events like keystrokes. Typeahead is a feature of computers and software (and typewriters, in days gone by) that enables users to continue typing regardless of program or computer operation - the user may type in whatever speed he desires, and if the receiving software is busy at the time it will be called to...
Interrupt routines generally have a short execution time. Most interrupt routines do not allow themselves to be interrupted, because they store saved (register) context on a stack, and if interrupted many times, the stack could overflow. An interrupt routine frequently needs to be able to respond to a further interrupt from the same source. If the interrupt routine has significant work to do in response to an interrupt, and it is not critical that the work be performed immediately, then often the routine will do nothing but schedule the work for some later time and return as soon as possible. Some processors support a hierarchy of interrupt priorities, allowing certain kinds of interrupts to occur while processing higher priority interrupts.
Processors also often have a mechanism referred to as interrupt disable which allows software to prevent interrupts from interfering with communication between interrupt-code and non-interrupt code. See mutual exclusion. Mutual exclusion (often abbreviated to mutex) algorithms are used in concurrent programming to avoid the concurrent use of un-shareable resources by pieces of computer code called critical sections. ...
Typically, the user can configure the machine using hardware registers so that different types of interrupts are enabled or disabled, depending on what the user wants. The interrupt signals are And'ed with a mask, thus allowing only desired interrupts to occur. Some interrupts cannot be disabled - these are referred to as non-maskable interrupts. In computing, a hardware register is a storage area for hardware I/O (input/output) of different kinds. ...
AND Logic Gate In mathematics, logical conjunction (usual symbol and) is a logical operator that results in false if either of the operands is false. ...
In computer science, a mask is some data that, along with an operation, are used in order to extract information stored elsewhere. ...
A non-maskable interrupt (or NMI) is a special type of interrupt used in most types of microcomputer, for example the IBM PC and Apple II. An NMI causes a CPU to stop what it was doing, change the instruction pointer to point to a particular address and continue executing...
A spurious interrupt is an IRQ that happens, but no interrupt handler is registered for the IRQ.
The phenomenon where the overall system performance is severely hindered by excessive amounts of processing time spent handling interrupts is called Interrupt Storm. In operating systems, an Interrupt Storm is the generally accepted jargon term for the phenomena where the overall system performance is severely hindered by excessive amounts of processing time spent handling interrupts. ...
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