switching
[′swich·iŋ]switching
(networking)switch
(1) A network cross connect. See Ethernet switch.(2) In programming, a bit or byte used to keep track of some event. The term is sometimes synonymous with the branch command.
(3) In programming, a statement that saves the programmer from having to write multiple compare statements. See event loop.
(4) A modifier of a command. For example, in the Windows/DOS command dir /p the /p is a switch that modifies the Dir command to pause after each screenful. See Dir.
(5) A mechanism that allows each key to be depressed on a keyboard. See mechanical keyboard.
(6) A mechanical or electronic device that directs the flow of electrical or optical signals from one side to the other. Switches with more than two ports, such as a LAN switch or PBX, are able to route traffic.
Not Entirely Intuitive
When a switch is closed, current flows and the light or motor is now "on." When opened, current stops, and the light or motor is off. Although "open" might seem to mean "turn something on," opening a switch turns it off, and vice versa. See transistor, Ethernet switch, softswitch, PBX and data switch.
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| Mechanical and Semiconductor Switches |
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| The semiconductor transistor performs the same function as a light switch on the wall. The switch is electronically closed by sending a pulse to the trigger. See transistor. |
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| A Manual Switch |
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| This early switch panel from New York Electric Switchboard Company was used to manually open and close electric lines. |
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task switching
Switching between applications that have been loaded in memory (are currently open). It generally refers to a user purposely jumping from one application to another, for example, by pressing Alt-Tab in Windows or Command-Tab in the Mac. See task switcher.Manual or Automatic
Context switching implies switching between applications that are open but dormant in the background, waiting to be resumed where they were left off. This is a manual form of task switching.
Multitasking implies automatic task switching, in which the operating system and applications cooperate in causing the computer to move from application to application in a round robin sequence. See multitasking.
Switching
(in physiology), one of the phenomena in the activity of the nervous system that improves an organism’s ability to adapt to the environment.
Switching can occur in various structures of the nervous system, for example, at the synapses; in the thalamus, where it participates in relay functions; and in the cerebral cortex, where it is involved with the formation of conditioned reflexes. Because of cortical switching, the interpretation of conditioned signals may change rapidly, depending on several factors, including the circumstances under which the signals are perceived. Thus, a conditioned stimulus, for example, the sound of a metronome, produces a feeding response when it is combined in the morning with the act of feeding, while during the day it promotes a defensive reaction when combined with electrical stimulation of an extremity. One signal thus can produce different conditioned responses, depending on the time of day. In this case, time is the factor that determines the conditioned response, as if it had the ability to switch one type of activity to another in the cerebral cortex.