"sequences. Keyboard shortcut In computing, a keyboard shortcut is a series of one or several keys, such as ""Ctrl+F"" to search a character string. Such a directive invokes a software or operating system operation (in other words, cause an event) when triggered by the user. The meaning of term ""keyboard shortcut"" can vary depending on software manufacturer. For instance, Microsoft differentiates keyboard shortcuts from hotkeys (""mnemonics"" on Windows) whereby the former consists of a specific key combination used to trigger an action, and the latter represents a designated letter in a menu command or toolbar button that when pressed together"
"referred to as touch events or gestures. Device events include action by or to a device, such as a shake, tilt, rotation, move etc. Event (computing) In computing, an event is an action or occurrence recognized by software, often originating asynchronously from the external environment, that may be handled by the software. Because an event is an entity which encapsulates the action and the contextual variables triggering the action we can use the acrostic mnemonic of an event as an ""Execution Variable Encapsulating Named Trigger"" to clarify the concept. Computer events can be generated or triggered by the system, by"
"System call In computing, a system call is the programmatic way in which a computer program requests a service from the kernel of the operating system it is executed on. This may include hardware-related services (for example, accessing a hard disk drive), creation and execution of new processes, and communication with integral kernel services such as process scheduling. System calls provide an essential interface between a process and the operating system. In most systems, system calls can only be made from userspace processes, while in some systems, OS/360 and successors for example, privileged system code also issues system calls. The"
"Command (computing) In computing, a command is a directive to a computer program acting as an interpreter of some kind to perform a specific task. Most commonly a command is either a directive to some kind of command-line interface, such as a shell, or an event in a graphical user interface triggered by the user selecting an option in a menu. Specifically, the term ""command"" is used in imperative computer languages. These languages are called this, because statements in these languages are usually written in a manner similar to the imperative mood used in many natural languages. If one views"
"form, enables a programmer to study and develop a sequence of steps known as an algorithm. Because the instructions can be carried out in different types of computers, a single set of source instructions converts to machine instructions according to the central processing unit type. The execution process carries out the instructions in a computer program. Instructions express the computations performed by the computer. They trigger sequences of simple actions on the executing machine. Those actions produce effects according to the semantics of the instructions. Computer software or just ""software"", is a collection of computer programs and related data that"
"Hooking In computer programming, the term hooking covers a range of techniques used to alter or augment the behavior of an operating system, of applications, or of other software components by intercepting function calls or messages or events passed between software components. Code that handles such intercepted function calls, events or messages is called a hook. Hooking is used for many purposes, including debugging and extending functionality. Examples might include intercepting keyboard or mouse event messages before they reach an application, or intercepting operating system calls in order to monitor behavior or modify the function of an application or other"
"Execution (computing) Execution in computer and software engineering is the process by which a computer or virtual machine executes the instructions of a computer program. Each instruction of a program is a description of a specific action to be carried out in order for a specific problem to be solved; as instructions of a program and therefore the actions they describe are being carried out by an executing machine, specific effects are produced in accordance to the semantics of the instructions being executed. Programs for a computer may be executed in a batch process without human interaction or a user"
"Event (computing) In computing, an event is an action or occurrence recognized by software, often originating asynchronously from the external environment, that may be handled by the software. Because an event is an entity which encapsulates the action and the contextual variables triggering the action we can use the acrostic mnemonic of an event as an ""Execution Variable Encapsulating Named Trigger"" to clarify the concept. Computer events can be generated or triggered by the system, by the user or in other ways. Typically, events are handled synchronously with the program flow, that is, the software may have one or more"
"Exec (system call) In computing, exec is a functionality of an operating system that runs an executable file in the context of an already existing process, replacing the previous executable. This act is also referred to as an overlay. It is especially important in Unix-like systems, although other operating systems implement it as well. Since a new process is not created, the original process identifier (PID) does not change, but the machine code, data, heap, and stack of the process are replaced by those of the new program. The ""exec"" call is supported in many programming languages, including compilable languages"
"to a user level process, e.g. I/O performed with a device present on the system, or any form of communication with other processes requires the use of system calls. A system call is a mechanism that is used by the application program to request a service from the operating system. They use a machine-code instruction that causes the processor to change mode. An example would be from supervisor mode to protected mode. This is where the operating system performs actions like accessing hardware devices or the memory management unit. Generally the operating system provides a library that sits between the"
"in computing, both for general data processing and for system ""housekeeping"" tasks (using system software). A high-level program (executing multiple programs, with some additional ""glue"" logic) is today most often called a ""script"", and written in scripting languages, particularly shell scripts for system tasks; however, in DOS this is instead known as a batch file. That includes UNIX-based computers, Microsoft Windows, macOS (whose foundation is the BSD Unix kernel), and even smartphones. A running script, particularly one executed from an interactive login session, is often known as a job, but that term is used very ambiguously. Batch applications are still"
"until termination. A program in execution is called a process. Termination is either by normal self-termination or by error – software or hardware error. Many operating systems support multitasking which enables many computer programs to appear to run simultaneously on one computer. Operating systems may run multiple programs through process scheduling – a software mechanism to switch the CPU among processes often so users can interact with each program while it runs. Within hardware, modern day multiprocessor computers or computers with multicore processors may run multiple programs. A computer program in execution is normally treated as being different from the"
"functions of the computer such as the input/output peripherals. Alternatively programmers might use these commands to copy software or even to circumvent the intent of a particular piece of software (e.g. manipulate a game program to allow the user to cheat). Today it is unusual to control computer memory at such a low level using a high-level language like BASIC. As such the notions of ""PEEK"" and ""POKE"" commands are generally seen as antiquated. The terms ""peek"" and ""poke"" are sometimes used colloquially in computer programming to refer to memory access in general. The PEEK function and POKE commands are"
"Fork (system call) In computing, particularly in the context of the Unix operating system and its workalikes, fork is an operation whereby a process creates a copy of itself. It is usually a system call, implemented in the kernel. Fork is the primary (and historically, only) method of process creation on Unix-like operating systems. In multitasking operating systems, processes (running programs) need a way to create new processes, e.g. to run other programs. Fork and its variants are typically the only way of doing so in Unix-like systems. For a process to start the execution of a different program, it"
"these primitives to compose new programs, or adapt existing ones to new uses or a changing environment. Programs for a computer might be executed in a batch process without human interaction, or a user might type commands in an interactive session of an interpreter. In this case the ""commands"" are simply programs, whose execution is chained together. When a language can run its commands through an interpreter (such as a Unix shell or other command-line interface), without compiling, it is called a scripting language. Determining which is the most widely used programming language is difficult since the definition of usage"
"Reentrancy (computing) In computing, a computer program or subroutine is called reentrant if it can be interrupted in the middle of its execution and then safely be called again (""re-entered"") before its previous invocations complete execution. The interruption could be caused by an internal action such as a jump or call, or by an external action such as an interrupt or signal. Once the reentered invocation completes, the previous invocations will resume correct execution. This definition originates from single-threaded programming environments where the flow of control could be interrupted by an interrupt and transferred to an interrupt service routine (ISR)."
"Selection (user interface) In computing and user interface engineering, a selection is a list of items on which user operations will take place. The user typically adds items to the list manually, although the computer may create a selection automatically. Selections are enacted through combinations of key presses on a keyboard, with a precision pointing device (mouse or touchpad and cursor, stylus), or by hand on a touchscreen device. The simultaneous selection of a group of items (either a subset of elements in a list, or discontinuous regions in a text) is called a ""multiple selection"". Context menus will usually"
"generally require a context switch to another process; instead, it is processed in the context of whichever process invoked it. In a multithreaded process, system calls can be made from multiple threads. The handling of such calls is dependent on the design of the specific operating system kernel and the application runtime environment. The following list shows typical models followed by operating systems: System call In computing, a system call is the programmatic way in which a computer program requests a service from the kernel of the operating system it is executed on. This may include hardware-related services (for example,"
"systems, upon receiving a boot signal from a human operator or a peripheral device, may load a very small number of fixed instructions into memory at a specific location, initialize at least one CPU, and then point the CPU to the instructions and start their execution. These instructions typically start an input operation from some peripheral device (which may be switch-selectable by the operator). Other systems may send hardware commands directly to peripheral devices or I/O controllers that cause an extremely simple input operation (such as ""read sector zero of the system device into memory starting at location 1000"") to"
"may type commands in an interactive session of an interpreter. In this case, the ""commands"" are simply program instructions, whose execution is chained together. The term run is used almost synonymously. A related meaning of both ""to run"" and ""to execute"" refers to the specific action of a user starting (or ""launching"" or ""invoking"") a program, as in ""Please run the application."" The context in which execution takes place is crucial. Very few programs execute on a bare machine. Programs usually contain implicit and explicit assumptions about resources available at the time of execution. Most programs execute with the support"
"or by replacing the operating system with a real-time operating system. There are several different types of software architecture in common use. In this design, the software simply has a loop. The loop calls subroutines, each of which manages a part of the hardware or software. Hence it is called a simple control loop or control loop. Some embedded systems are predominantly controlled by interrupts. This means that tasks performed by the system are triggered by different kinds of events; an interrupt could be generated, for example, by a timer in a predefined frequency, or by a serial port controller"
"Exploit (computer security) An exploit (from the English verb ""to exploit"", meaning ""to use something to one’s own advantage"") is a piece of software, a chunk of data, or a sequence of commands that takes advantage of a bug or vulnerability to cause unintended or unanticipated behavior to occur on computer software, hardware, or something electronic (usually computerized). Such behavior frequently includes things like gaining control of a computer system, allowing privilege escalation, or a denial-of-service (DoS or related DDoS) attack. There are several methods of classifying exploits. The most common is by how the exploit communicates to the vulnerable"
"Active Setup Active Setup is a mechanism for executing commands once per user early during login. Active Setup is used by some operating system components like Internet Explorer to set up an initial configuration for new users logging on for the first time. Active Setup is also used in some corporations’ software distribution systems to create an initial customized user environment. Active Setup uses both machine-specific data and user-specific data. The machine part consists of a list of components identified by a GUID each. The user part is basically a mirror of the machine data, but it does not initially"
"while large operating systems built by huge groups of software engineers with large budgets would more often opt to write their own drivers instead of using BIOS—that is, even without considering the compatibility problems of BIOS and protected mode. BIOS interrupt call BIOS interrupt calls are a facility that operating systems and application programs use to invoke the facilities of the Basic Input/Output System on IBM PC compatible computers. Traditionally, BIOS calls are mainly used by DOS programs and some other software such as boot loaders (including, mostly historically, relatively simple application software that boots directly and runs without an"
"suggest that they are very easy to use, requiring that the user simply point to indicate their wishes. These interfaces are sometimes referred to condescendingly (e.g., by Unix users) as ""click-and-drool"" or ""point-and-drool"" interfaces. The use of this phrase to describe software implies that the interface can be controlled solely through the mouse (or some other means such as a stylus), with little or no input from the keyboard, as with many graphical user interfaces. In some systems, such as Internet Explorer, moving the pointer over a link (or other GUI control) and waiting for a split-second (that can range"
"to or built into the computer. A ""user interface"" ""allows users to interact with a computer."" Either a command-line interface (CLI) or, since the 1980s a graphical user interface (GUI). Since this is the part of the operating system the user directly interacts with, it may be considered an application and therefore not system software. For historical reasons, some organizations use the term ""systems programmer"" to describe a job function which is more accurately termed systems administrator. Software tools these employees use are then called system software. This so-called ""Utility software"" helps to analyze, configure, optimize and maintain the computer,"
"above the appropriate track. This is also known as rotational latency and seek time since the basic term latency is also applied to the time required by a computer's electronics and software to perform polling, interrupts, and direct memory access. Computers run sets of instructions called a process. In operating systems, the execution of the process can be postponed if other processes are also executing. In addition, the operating system can schedule when to perform the action that the process is commanding. For example, suppose a process commands that a computer card's voltage output be set high-low-high-low and so on"
"Interaction technique An interaction technique, user interface technique or input technique is a combination of hardware and software elements that provides a way for computer users to accomplish a single task. For example, one can go back to the previously visited page on a Web browser by either clicking a button, pressing a key, performing a mouse gesture or uttering a speech command. It is a widely used term in human-computer interaction. In particular, the term ""new interaction technique"" is frequently used to introduce a novel user interface design idea. Although there is no general agreement on the exact meaning"
"to provide the I/O to allow drivers to physically access their devices through some port or memory location. Very important decisions have to be made when designing the device management system, as in some designs accesses may involve context switches, making the operation very CPU-intensive and easily causing a significant performance overhead. In computing, a system call is how a process requests a service from an operating system's kernel that it does not normally have permission to run. System calls provide the interface between a process and the operating system. Most operations interacting with the system require permissions not available"
"call to the application program; the OS provides a library of user functions with names corresponding to each actual system call. Each of these stub functions contains a trap to the OS function. When the application program calls the stub, it executes the trap instruction, which switches the CPU to kernel mode, and then branches (indirectly through an OS table), to the entry point of the function which is to be invoked. When the function completes, it switches the processor to user mode and then returns control to the user process; thus simulating a normal procedure return. In the message"
"a standardized way to programs, including operating systems. For example, an IBM PC might have either a monochrome or a color display adapter (using different display memory addresses and hardware), but a single, standard, BIOS system call may be invoked to display a character at a specified position on the screen in text mode or graphics mode. The BIOS provides a small library of basic input/output functions to operate peripherals (such as the keyboard, rudimentary text and graphics display functions and so forth). When using MS-DOS, BIOS services could be accessed by an application program (or by MS-DOS) by executing"
"Coroutine Coroutines are computer-program components that generalize subroutines for non-preemptive multitasking, by allowing multiple entry points for suspending and resuming execution at certain locations. Coroutines are well-suited for implementing familiar program components such as cooperative tasks, exceptions, event loops, iterators, infinite lists and pipes. According to Donald Knuth, Melvin Conway coined the term ""coroutine"" in 1958 when he applied it to construction of an assembly program. The first published explanation of the coroutine appeared later, in 1963. Subroutines are special cases of coroutines. When subroutines are invoked, execution begins at the start, and once a subroutine exits, it is finished;"
"of the term ""shell"" means any program that users employ to type commands. A shell hides the details of the underlying operating system and manages the technical details of the operating system kernel interface, which is the lowest-level, or ""inner-most"" component of most operating systems. In Unix-like operating systems, users typically have many choices of command-line interpreters for interactive sessions. When a user logs into the system interactively, a shell program is automatically executed for the duration of the session. The type of shell, which may be customized for each user, is typically stored in the user's profile, for example"