Services of the Kernel I/O Subsystem

In Topic 2, we discussed 10 different service types that an OS provides. One of these was handling I/O requests. Some particular I/O services that an OS provides are:

1. I/O Scheduling: It is critical, in terms of efficiency, for the OS to decide in which order I/O requests will be handled.
   • Various CPU scheduling algorithms could be used to determine the most efficient order.
   • The choice of an algorithm depends on what we are trying to achieve: increased throughput, faster multitasking, shorter response time, etc.
   • Every algorithm achieves one of these goals but might undermine another.
   • A device-status table stores all the I/O operations that will occur on an I/O device.
   • We will cover more on CPU Scheduling in Topic 6.