Jiffy

the English term Jiffy (also Jiffie) designates a short, frequently more near not specified time interval. In the science and computer engineering “Jiffy” knows different, in each case time intervals defined for application and/or. Time units indicate. The most frequent interpretation is 1/100 second, which represents about the smallest manually still measurable length of time. Jiffy describes (and/or. corresponds) depending upon publication or group of users:

There are still further interpretations for the term Jiffy, whose exact origin is not clarified, in 18. Century in England to have been coined/shaped is. It designated a short, however indefinite time already at that time. In the English colloquial language today the still common “in A jiffy” is comparably with the German “in an instant /a Sekündchen ", or also “in a flash”.

use within the range of the operating systems

a Jiffy is operating system and depending on hardware unit for the number of necessary time slots (English. timeslices) the one process for a certain procedure needs.

The term is in particular in the UNIX - world, common, where a Jiffy stands for the period duration of the timer interrupt. Synonymously for it Microsoft uses the term quantity.

On Linux systems in addition a global variable of jiffies , which is increased by the Kernel with each occurrence of the timer interrupt by unity, exists. With the system start this variable with the value 0 is initialized. The frequency of the increase depends strongly on the processor, as well as the overall system, and may lie with Linux systems between 12 and 1535 cycles per second, from which however only few are recommendable due to restrictions by architecture and the NTP.

literature

 

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