Secondary Storage Devices Ahijah Lane Secondary Storage Devises: A storage medium that holds information until it is deleted or overwritten. QuickTim e™ a nd a TIFF (Un com pre ssed) decom presso r are neede d to see this p icture. Magnetic Tape Storage: - is a 1/4 inch or 1/2 inch ribbon of plastic material on which data is recorded. It reads, writes and erases data on tapes. - Magnetic tapes are erasable, reusable and durable and made to store large quantities of data. Magnetic Disk Storage: - Magnetic disks are the most widely used storage medium for computers. - It offers high storage capacity, reliability, and the capacity to directly access stored data while holding more data. Types of Magnetic Disk Storage: • Diskettes: Introduced in early 1970s by IBM as a new type of secondary storage. Originally they were thin and flexible which gave them the name floppy disks. • used as the principle medium of secondary storage for personal computers. • Hard Disks: Hard disks provide larger and faster secondary storage capabilities than diskettes. Usually hard disks are permanently mounted inside the computer with 2-4 disk drives. • Disk Cartridges: Offer the storage and fast access of hard disks and the portability of diskettes. • More secure because the disk cartridge can be removed and locked up leaving no data on the computer. Recovery Devices: • Backup: creating a copy of important programs and data. To backup diskettes, copy the data from one to the other. Diskettes are frequently used to backup important files on hard drives of personal computers. • Data Recovery: There does exist certain software programs that can recover data and programs that have been "lost." Often your operating system will be able to do this. Overview: Storage Speed Capacity Relative Permanent? Cost ($) Hard Disk Moderate Very High Very Low Yes Registers Fastest Lowest Highest No Floppy Very Slow Low Low Yes Disk RAM Very Fast Low/Moderat High No e Benefits of Secondary Storage: • Capacity. Organizations may store the equivalent of a roomful of data on sets of disks that take up less space than a breadbox. • Reliability. Data in secondary storage is basically safe, since secondary storage is physically reliable. • Convenience. With the help of a computer, authorized people can locate and access data quickly. • Cost. It is less expensive to store data on tape or disk than filing cabinets, but the greatest savings can be found in the speed and convenience of filing and retrieving data.
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