uniti secondary memory read-only memory (romromo stores information permanently in the computer its name is read-onlybecause computer can read but cannot write information in rom rom is non-volatile data stored in rom do not disappear when the computer is switched off secondary storage devices these devices are needed for the following reasons computers need permanent semi permanent storageso that information can be retained during power-loss or when the computer is turned off systems typically store more information than will fit in memory some of the most frequently used secondary storage devices compact diskmagnetic tapefloppy diskhard diskzip diskdigital video disk input output devicesinput output devices are used to communicate with the computer they allow us to enter data for computation and to observe the results of that computation department of csevishnu institute of technology