Optical Storage Devices by Jayanth n praneeth

Optical Storage Media : 

1 Optical Storage Media Optical storage devices save data as patterns of dots that can be read using light. A laser beam is the usual light source.The data on the storage medium is read by bouncing the laser beam off the surface of the medium. If the beam hits a dot it is reflected back differently to how it would be if there were no dot. This difference can be detected, so the data can be read.Dots can be created using the laser beam (for media that is writable such as CD-RW). The beam is used in a high-power mode to actually mark the surface of the medium, making a dot. This process is known as ‘burning’ data onto a disc. Optical storage devices save data as patterns of dots that can be read using light. A laser beam is the usual light source. types of optical storage devices 1 Read-Only Optical Discs 2Recordable Optical Discs

Read-Only Optical Discs : 

2 Read-Only Optical Discs Recordable optical discs can have data written onto them (‘burnt’) by a computer user using a special disc drive (a disc ‘burner’). Recordable optical discs can have data written onto them (‘burnt’) by a computer user using a special disc drive (a disc ‘burner’). read-only optical discs have data written onto them when they are manufactured. This data cannot be changed. Types of read – only optical discs Cd-ROM Dvd-ROM CD-ROM:- Compact Disc - Read-Only Memory (CD-ROM) discs can hold around 800MB of data. The data cannot be altered (non-volatile), so cannot be accidentally deleted. CD-ROMs are random-access devices .CD-ROMs are used to distribute all sorts of data: software (e.g. office applications or games), music, electronic books  DVD-ROM:- Digital Versatile Disc - Read-Only Memory (DVD-ROM) discs can hold around 4.7GB of data (a dual-layer DVD can hold twice that). DVD-ROMs are random-access devices. DVD-ROMs are used in the same way as CD-ROMs (see above) but, since they can hold more data, they are also used to store high-quality video

Recordable Optical Devices : 

3 Recordable Optical Devices Rcordable optical discs can have data written onto them (‘burnt’) by a computer user using a special disc drive (a disc ‘burner’) types of recordable optical devices CD-R DVD-R DVD-RW CD-R

CD-R and DVD-RCD-RW and DVD-RW : 

4 CD-R and DVD-RCD-RW and DVD-RW CD-Recordable (CD-R) and DVD-recordable (DVD-R) discs can have data burnt onto them, but not erased. You can keep adding data until the disc is full, but you cannot remove any data or re-use a full disc CD-Re-Writable (CD-RW) and DVD-Re-Writable (DVD-RW) discs, unlike CD-Rs and DVD-Rs, can have data burnt onto them and also erased so that the discs can be re-used.

Questions!!! : 

5 Questions!!! Question 1-What are two types of optical storage devices? Question 2-What are the types of recordable storage device? Question 3- What are the types of read only optical storage devices? Question 4- Using what are they read?