Search results
Results from the WOW.Com Content Network
Input/output (I/O) scheduling is the method that computer operating systems use to decide in which order I/O operations will be submitted to storage volumes. I/O scheduling is sometimes called disk scheduling .
The scheduler is an operating system module that selects the next jobs to be admitted into the system and the next process to run. Operating systems may feature up to three distinct scheduler types: a long-term scheduler (also known as an admission scheduler or high-level scheduler), a mid-term or medium-term scheduler, and a short-term scheduler.
In computing environments that support the pipes-and-filters model for interprocess communication, a FIFO is another name for a named pipe.. Disk controllers can use the FIFO as a disk scheduling algorithm to determine the order in which to service disk I/O requests, where it is also known by the same FCFS initialism as for CPU scheduling mentioned before.
Although the two-state process management model is a perfectly valid design for an operating system, the absence of a BLOCKED state means that the processor lies idle when the active process changes from CPU cycles to I/O cycles. This design does not make efficient use of the processor.
In computer science, The System Contention Scope [1] is one of two thread-scheduling schemes used in operating systems.This scheme is used by the kernel to decide which kernel-level thread to schedule onto a CPU, wherein all threads (as opposed to only user-level threads, as in the Process Contention Scope scheme) in the system compete for the CPU. [2]
Anticipatory scheduling overcomes deceptive idleness by pausing for a short time (a few milliseconds) after a read operation in anticipation of another close-by read requests. [2] Anticipatory scheduling yields significant improvements in disk utilization for some workloads. [3]
Shortest seek first (or shortest seek time first) is a secondary storage scheduling algorithm to determine the motion of the disk read-and-write head in servicing read and write requests. Description [ edit ]
In other words, if the I/O paths are not saturated and the requests for all the workloads fail to cause an unreasonable shifting around of drive heads (which the operating system is aware of), the benefit of prioritizing one workload may create a situation where CPU time spent scheduling I/O is wasted instead of providing desired benefits.