Input output management

Wednesday, August 14, 2013

Input output management

Device management is perhaps an operating system’s greatest challenge. The operating system must control a collection of devices with multidimensional difference. Device differs in their speed, information volume, purpose and the communication protocols. On some system thousands of different devices could potentially be connected to the machine, each of which requires its own unique operating system support. An all of this management must be accomplished in an environment of parallelism. Device must operate mostly independent of the CPU.
One of the main functions of an operating system is to control all the computer’s I/O (Input/Output) devices. It must issue commands to the devices, catch interrupts, and handle errors. It should also provide an interface between the devices and the rest of the system that is simple and easy to use. To the extent possible, the interface should be the same for all devices (device independence).

Although it must be deal with a diverse set of devices, the abstraction presented to applications should be as device independent as possible. The physical characteristics of floppy disks, CD ROMs, printer and main memory vary greatly, but application should be able to read from or write to them as if they were all the same.