Primary Storage of today's computer system has following limitations -
Limited capacity. It is often necessary to store many millions, sometimes billions, and even trillions, of bytes of data in a computer. Unfortunately, storage capacity of primary storage of today's computers is not sufficient to store the large volume of data handled by most data processing center.
Volatile. Primary storage is volatile and it loses data stored in it in case of power off or interruption of power. However, computer systems need to store data on permanent basis for several months, or even several years.
To overcome the limitations of primary storage, almost all computers use additional memory called auxiliary memory or secondary storage. Secondary storage non-volatile and has lower cost per bit stored, but operates generally at speeds far slower than that of primary storage. Computer systems use it primarily to store large volume of data on permanent basis, which they transfer partially to primary storage, whenever required for processing.
Over the years, computers systems have used several devices and media as secondary storage. Many of them such as punched paper tape, punched cards, and floppy disks have become obsolete now. shows the popular ones used in today's computer systems. In this you will learn about the terminologies, principles of operation, uses, and trade-offs of different types of secondary storage devices.