UNIT 3: STORAGE DEVICES AND MEDIA
3.1 BACKING UP DATA:
WHAT IS BACKING UP OF DATA?
Backing up refers to the copying of files and data to a different medium (disk, tape, flash drive, etc.)
Backing up files and data on a regular basis is seen as good computing practice and many computer systems can be easy to back up the files automatically on a regular basis.
Backing up refers to the copying of files and data to a different medium (disk, tape, flash drive, etc.)
Backing up files and data on a regular basis is seen as good computing practice and many computer systems can be easy to back up the files automatically on a regular basis.
WHY BACK UP DATA?
Some of more common reasons are considered below:
+ Data could be lost if the computer is broken
+ Hackers could steal information from computer or destroy the computer system
+ Backups are easy for us to use the files everywhere we want
Some of more common reasons are considered below:
+ Data could be lost if the computer is broken
+ Hackers could steal information from computer or destroy the computer system
+ Backups are easy for us to use the files everywhere we want
3.2 TYPES OF ACCESS:
SERIAL ACCESS:
It is necessary to start at the beginning and then access each piece of data in turn until the necessary information is found.
It is primarily used on magnetic tape systems and is a very slow form of access. It is used in applications where speed of access or where the order in which the data is accessed is not important
DIRECT ACCESS:
This method is used with magnetic disks and with optical media (such as CDs and DVDs)
The computer uses a key field to calculate where data has been stored.
It is then able to access the data directly from the calculate position. Consequently, access is much faster than with serial access.
The new data is written to the next available location and its position is calculated using the built-in algorithm.
It is necessary to start at the beginning and then access each piece of data in turn until the necessary information is found.
It is primarily used on magnetic tape systems and is a very slow form of access. It is used in applications where speed of access or where the order in which the data is accessed is not important
DIRECT ACCESS:
This method is used with magnetic disks and with optical media (such as CDs and DVDs)
The computer uses a key field to calculate where data has been stored.
It is then able to access the data directly from the calculate position. Consequently, access is much faster than with serial access.
The new data is written to the next available location and its position is calculated using the built-in algorithm.
3.3 BACKING STORAGE MEDIA
Backing storage devices ensure that data is stored permanently and can be used at a later date.
Backing storage devices are either internal or external to the computer, and are one of three types:
+ magnetic
+ optical
+ solid state
Backing storage devices are either internal or external to the computer, and are one of three types:
+ magnetic
+ optical
+ solid state