Backing Storage

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Disk

Disk storage is a general category of storage mechanisms where data is recorded by various electronic, magnetic, optical or mechanical changes to a surface layer of one or more rotating disks. A disk drive is a device implementing such a storage mechanism. 

Pen drives

A pen drive is a portable Universal Serial Bus (USB) flash memory device for storing and transferring audio, video and data file from a computer. As long as the desktop or laptop has a USB port, and the pen drive is compatible with operating system, it should be easy to move the data from the hard drive to the device and to another computer in a matter of minutes.

Optical media

• Optical media is a flat and circular disk which is coated with reflective plastic material that can be altered by laser light.
• It consist a single spiral track that starts from the edge to the center of disk. 
• Due to its spiral shape, it can access large amount of data sequentially, for example music and video. 
• Optical disks can store large amount of data, up to 6 GB in a small space. Commonly used optical disks store 600-700 MB of data.
• Optical Disk are generally slower than hard disks.

Flash memory cards

A flash memory card is a small storage device that uses non-volatile semiconductor memory to store data on portable or remote computing devices. Such data includes text, picture, audio and video. Most current products use flash memory, although other memory technologies are being developed, including devices that combine dynamic random access memory with flash memory.

Portable and fixed drives

Portable and fixed drives are used to backup work. Portable drives can be plugged into the computer port whenever you need it and you can take it out when not in use, it's used to store large files which need transporting from one computer to another. Fixed hard disk is used to store operating system and not for storing applications which we need portability. Furthermore, it stores any application which requires very fast access to data for reading and writing.