Objectives of the I/O Management in Operating System:
The objectives of the I/O Management module are as follows:
1. Generality and Device Independence:
I/O devices are typically quite complex mechanically and electronically. Much of this complexity is related to the electronic engineering and is of no interest to the user or the programmer. The average user is not aware of the complexities of positioning the heads on a disk drive, reading the signal from the disk surface, waiting for the required sector to rotate into position etc.
Users and programmers may be unaware of this complexity. The I/O management module must try to treat all external devices uniformly. This is achieved by virtual device. A virtual device is a special kind of file that is associated with a particular external device. Users create a virtual device of a given type, and operating system associates a physical device with it when the device is required for the first time. All virtual devices in a system are stored in a liked list.
2. Efficiency:
Perhaps the most significant characteristic of the I/O system is. the speed disparity between it and the processor. I/O devices involve mechanical operations. They cannot compete with the microsecond or nanosecond speed of the processor and memory. The I/O management module must try to minimize the disparity by the use of techniques like buffering and spooling.
