Secondary storage

Dick caching



Disk caching is a mechanism to improve the time needed to read/write onto a hard disk. It is usually part of the hard disk. It holds data that has been most recently used in order to speed up the access of that data. When a program needs to access new data, the operating system checks if the data is in the cache before reading it from the disk. Data from the RAM can access much faster than from a disk, disk caching helps increase performance.




File Compression


File compression is commonly used when sending a file from one computer to another over a connection that has limited bandwidth. The compression basically makes the file smaller and, therefore, the sending of the file is faster. Of course, when compressing a file and sending it to another computer that computer has to have a program that will decompress the file so it can be returned to "normal" and used.

File decompression is when you return the file to its original size by extracting it or unarchiving it. Sending and receiving compressed files across the Internet is a common activity.




Internet Hard Drive

Internet hard drives enable the users to backup their files on the Internet through many backup servies available.Backing up files on the Internet may take a long time, as it depends on the speed of the internet. Likewise, uploading your file back on the computer may also take a long time. However, what internet hard drive offers is the freedom to retrieve any document you need from anywhere in the world.




Optical Diskdrive

The optical disc drive (ODD) is a disk drive which uses low-powered laser light or electromagnetic waves near the light spectrum to read or write data to or from optical discks. Optical disc drivs are circular, flat, glass or plast disk in which data can be stored in the form of light and dark pits.  Often, ODD are called burners or writers. CD's, DVD's and blu-ray discs are the common types of optical media that can be read and written on by such drives.




Solid State Storage

A solid-state storage is a type of nonvolatile, removable data storage device which uses solid-state memory to keep persistent data. It is distinguished from traditional hard disk drives, which are electromechanical devices containing spinning disks and movable read/write heads since solid-state storage does not contains any mechanical parts.