DVD is a form of optical storage. The data on a DVD is read by an optical reader.

In a magnetic disk assembly, Spindle is the central cylindrical rod, Read write head is used to read and write data and the arm is used to hold the magnetic disk.

Data is retained in flash memory. Power losses do not affect the data stored in flash memory.

The mean time to failure is the measure of the reliability of a disk. It gives the mean of the times that most disks last.

The time for repositioning the arm is called as Seek time.

Cache storage is very fast but it is the costliest form of storage.

The time from when a read or write request is issued to when the actual data transfer begins is called access time. Data transfer rate is the rate at which data can be retrieved from the storage.

USB – Universal Serial Bus. This is currently the most popular and convenient way of data transmittal.

When a large number of disks are connected by a high speed network to a number of server computers, it is known as Storage Area Network (SAN) architecture. These disks are usually arranged by a local organization technique called RAID.

Buffering involves reading the data and storing it in a temporary memory location called as the data buffer for future requests. The data in the buffer is temporary and is deleted after usage.