Data storage.

Data storage.

For smarter and faster than the memory of a computer can be, the RAM is faulty unforgivable. It volatile
as marsh fire. With rare exceptions, to turn off the computer all memory chips lose the information
stored. The work you had to organize the budget figures next year, creating accounting documents
or enter a large compendium disappear if there are any electrical problem that prevents, even for a split
Second, the continuous supply of energy in the transistors of the RAM chips.

Luckily, there are several ways to permanently store computer programs and the work done with them - all
data is maintained even when the power is turned off. The most common way to permanent storage
occurs via the magnetic disks - both flexible as the wide variety of drives. Magnetic storage is
also used in the form of ribbons - a method of permanent recording almost as old as the first computers. The
storage devices and data recovery using lasers are gaining popularity. Recently,
computer manufacturers started to search the creation of non-volatile chips, unlike the common RAM chips,
may maintain its contents when the PC is turned off, because they have their own built-in power supplies. All of these
methods for permanent data storage advantages and disadvantages.

Floppy disks are universal, portable and cheap, but lost in storage capacity and speed. Discs
drives are still probably the best storage medium. Save and retrieve data quickly, allow you to record
several volumes of data and are not expensive taking into account the cost per megabyte. But they are generally not
portable except the latest versions and much more expensive. The tapes allow, strictly speaking, the infinite storage data
at low cost, but they are too slow for any purpose other than to serve as backup.

Some of the newer forms of storage meet PC users who need to store large amounts of
data. The CD-ROM stores up to 500 megabytes of data on a disk identical to the CDs that contain music. Discs
CD-ROM are cheap to produce, but they are only reading devices, meaning you can only use the data that
already stored in them come, it can not use them to store new data. The magneto-optical drives, such as CD-ROMs,
use lasers to read data but have the advantage of also able to record data. Are fast, portable and, in general, have
large storage capacity, but only recently the cost has dropped enough to make them more accessible.

Two types of memory chips retain their information when the computer is turned off. The EPROM (Erasable acronym
Programmable Read-Only Memory) memories are erasable and programmable read-found on most computers
personal. They have the role of providing information to boot the PC, but are slow and their data can only
be altered after exposure to ultraviolet light. The fast RAM chips (flash RAM) which combine the possibility of
recording and greater flexibility than the conventional RAM chips with the ability to retain data when power is
cut may be quite common in the future and to become an ideal medium for permanent storage. But for now,
are still too expensive to completely replace the hard drives.

Despite the different technologies used in the methods of storage, all have a common notation for recording
data and a similar system for storing information so that they can be found again. Storage
permanent data is similar to the concept adopted by the filing systems of roles. Paper files need
be handwritten or typed, but have the same language. If they were randomly stored in drawers
files, it would be impossible to find them easily and quickly. The electronic files, likewise, have to be
stored in a certain order within a logical system, and written in a common language.

Source: Evolution of Computers