Transcript Secondary Storage Devices

Secondary
Storage
Devices
Ahijah Lane
Secondary Storage
Devises:
A storage medium that holds information
until it is deleted or overwritten.
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T IFF (Unco m p re sse d ) d e com pre ssor
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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
Cost ($)
Permanent?
Hard Disk
Moderate
Very High
Very Low
Yes
Registers
Fastest
Lowest
Highest
No
Floppy
Disk
RAM
Very Slow
Low
Low
Yes
Very Fast
Low/Moderat
e
High
No
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.