text: what are the speed, functionality and importance of input and output? based on examples of business environments speed is usually measured in baud or bits..more commonly measured in bits. functonality depends on what you are talking about..are you talking about hard disk i/o or ram or bus ?  importance...well compatability issues arise or perhaps memory or disk speeds that are too slow will create traffic jams and lock up your system.  basically, the speed or i/o measures the ability of a device to read and write data.