Storage 

Storage 

Storage is also known as secondary storage, auxiliary storage, permanent storage, or mess storage. It is used to store data, instructions, and information permanently. It is called nonvolatile because its contents remain safe even if the computer is turned off.

The different storage medium is used to store data and information such as floppy disk, hard disk, and compact disk. A hardware unit that is used to stone and retrieve data to and from a storage medium is called a storage device. Two important functions of a storage device are leading and writing.

 

1. Reading: The process of copying data, instructions, or information from the storage medium to memory is called reading.
2. Writing: The process of copying the data, Instructions, or information from memory to a storage medium is called writing.

The time in which a device locales an item on a storage medium is called access time Access time of storage devices is slower than a memory. The number of bytes that can be stored on a storage medium is called it's capacity.

 

Difference between Memory and Storage

The difference between memory and storage is as follows:

Memory:

1. Memory is volatile.
2. It is faster than storage.  

1. It is more expensive than storage.
2.  It is smaller in size than storage.
3.  Programs are copied from storage when during execution.
4.  The capacity of memory is less storage.

 

Storage:

1. Storage is nonvolatile.
2. It is slower than a memory.
3. It is less expensive than a memory.
4. It is bigger in size than a memory.
5.  Programs being stored in storage no execution takes place.
6.  The capacity of storage is much more than a memory.

 

Levels of Storage Hierarchy

The three levels of storage hierarchy are:

1. Online storage: Also called primary storage, it is made up of the storage devices that are actively available to the computer system. User action is not required.
2. Near-0min: storage: Also called secondary storage it is not readily available to the computer system. The user performs an action, such as inserting a disk, to make it available.
3. Offline storage: Also called tertiary storage or archival storage, it is not readily available to the computer system Devices such as tape backup unit store data for archival purposes.

• Storage Devices