MBA
Storage
Devices
Data
storage is a critical component of any computer system. Magnetic storage is one
of the most affordable ways to store large amounts of data and has been
implemented using magnetic tape, floppy disks and hard disk drives.
Introduction (Magnetic
Storage Devices)
Computer systems need
to store data in digital format. One of the most widely used types of digital
data storage is magnetic storage. This refers to any type of data
storage using a magnetized medium. Digital data consists of binary
information, which is data in the form of zero and ones. There are two
types of magnetic polarities, each one used to represent either zero or one.
Several types of
magnetized media are used in computer systems, including magnetic tape, floppy
disks and hard disk drives. The basic approach to magnetic
data storage, however, is very similar for the different types of media. A
read-write head moves very close to the magnetic surface - the distance is
often no more than tens of nanometers. The head is able to detect and modify
the magnetization of the material. The magnetic surface is divided into very
small regions, each of which has a mostly uniform magnetization. As the head
moves relative to the surface, the changes in magnetization from region to region
are detected and recorded as zeros and ones. Different technologies vary in how
the head moves relative to the surface of the media and how the regions on the
media are organized, but the basic principle is the same.
Magnetic storage is a
form of non-volatile storage. This means that the data is not lost
when the storage device is not powered. This is in contrast to volatile
storage, which is typically used for the main memory of a computer system.
Volatile storage requires a constant power supply - when a computer system is
turned off, the data is lost.
Magnetic storage is
widely used because it is relatively cheap in comparison with other storage
technologies. Magnetic storage is read-write, which makes it possible to re-use
the storage capacity over and over again by deleting older data. The storage
capacity is also very large, making it attractive for storing very large
amounts of data. The major limitation of magnetic storage is that accessing the
data can be quite slow. As a result, most computer systems use magnetic storage
for non-volatile storage of large amounts of data (typically in a form of a
hard-disk drive) but a different type of storage for system memory, such as
read-only memory (RAM), which is much smaller but can be accessed much faster.
Types of Magnetic
Storage Devices
Magnetic tape is one
of the older types of magnetic storage media. The magnetic tape recorder was
invented in 1928 and was primarily used for analog audio recordings. Before
music CDs were introduced in the 1980s, portable music devices used magnetic
tape in the form of music cassettes. Early computers adapted this
technology to store digital information. One of the major weaknesses is that
information on a tape can only be accessed in a very sequential fashion. This
is fine if you want to listen to a whole music album in sequence, but computer
systems typically need to access data in a non-sequential manner. For magnetic
tape, this means you may need to fast forward through a lot of tape to get to a
specific piece of data. While magnetic tape is a very cheap way to store data,
the very slow access to the data meant that it was primarily used for creating
backups of data in case older forms of storage failed. Tape backup systems are
still in use today, but their importance has greatly declined with the advance
of cheap, large capacity hard-disk drives.
Magnetic tape data storage system
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Types of Magnetic Storage Devices
There are several
different ways of storing information on the computer. One of the longest used
systems for storing information have been with magnetic storage devices.
Magnetic storage devices have improved in capacity and speed since they were
first used. Smaller devices can now hold much more information. Even though
other types of storage are becoming more popular, there are still many uses for
magnetic storage devices.
These are the most commonly
known magnetic storage devices.
Hard Drive
Inside the hard drive is a
magnetic platter that stores all your information.
Most computer hard
drives are magnetic, even today in 2010. The hard drive is where the computer's
operating system and programs are stored. Without the hard drive, the computer
would have to run off a disk that held not only the operating system, but any
other programs that were needed. Running everything from a disk other than the
hard drive will slow the entire system down.
Floppy
Disk
The
original floppy disk was floppy and flimsy in texture. During the evolution of
the floppy disk, they went from 80 kilobytes of storage up to 2880 kilobytes of
storage (2.88 megabytes). The most known floppy drives are the 5 1/4-inch 720
kilobyte disk and the 3 1/2-inch 1.44 megabyte disk.
Tape
Flash Memory- A kind of memory that
retains data in the absence of a power supply.
"The
diagnostics are kept in flash memory"
Flash memory is widely used with car radios, cell
phones, digital cameras, PDAs, solid-state drives, and printers.
The picture is an example of a MicroSD flash memory
Alternatively referred to as flash storage, flash
memory is non-volatile computer
memory. It was first invented by Fujio Masuoka in
the early 1980s while at Toshiba and
introduced it to the market in 1984. It was also later developed by Intel. Flash memory is an integrated circuitthat
does not need continuous power to retain data, but is a bit more expensive
than magnetic storage.
Today, flash memory is very popular and solid-state drives are
a practical replacement for large hard drives if
you have the extra money.
Flash memory is widely used with car radios, cell phones, digital cameras, PDAs, solid-state drives,
and printers.
The picture is an example of a MicroSD flash memory card. For additional
information and examples, see our flash memory card page.
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