8/6/2019 h Holographic

1/17

8/6/2019 h Holographic

2/17

MAGNETIC STORAGE WITH LIMITEDSPACE

LESS MOBILITY

EXPENSIVE

SLOW TO ACCESS

MOBILE STORAGE WITH VERY LESS

STORAGE

8/6/2019 h Holographic

3/17

With the technological advancements thestorage even advanced for more reliableand better media for the permanent

storageThe magnetic storage devices are mostly

used but they are more prone to

corruption.So to avoid that the losses due tocorruption special data is stored in someother media.

8/6/2019 h Holographic

4/17

1.CD

2.DVD

3.BLU-RAY DISC

4.HVD*

8/6/2019 h Holographic

5/17

CD (commonly stands for compact disc) is oneof the oldest and most commonly used opticalmedia for storage.

It is generally of a standard size of with 8cmdiameter but a mini-CD is now available with alesser diameter and a storage capacity of just250Mb.

A normal CD of 12cm diameter has a storagecapacity of 700Mb of data

8/6/2019 h Holographic

6/17

DVD (also known as Digital Versatile Disc or DigitalVideo Disc) is a popular optical disc storage mediaformat. Its main uses are video and data storage. Most

DVDs are of the same dimensions as compact discs(CDs) but store more than six times as much data.

Variations of the term DVD often describe the way data isstored on the discs: DVD-ROM has data which can onlybe read and not written, DVD-R and DVD+R can only

record data once and then function as a DVD-ROM. DVD-RW, DVD+RW and DVD-RAM can both record and erasedata multiple times.

8/6/2019 h Holographic

7/17

DESIGANATION SIDES

LAYERS

DIAMETER(cm)

CAPACITY(Gb)

DVD 1 SS SL 1 1 8 1.46

DVD 2 SS DL 1 2 8 2.66DVD 3 DS SL 2 2 8 2.92

DVD 4 DS DL 2 4 8 5.32

DVD 5 SS SL 1 1 12 4.

DVD 9 SS DL 1 2 12 8.54

DVD 1 DS SL 2 2 12 9.4

DVD 14 DSDL/SL

2 3 12 13.24

DVD 18 DS DL 2 4 12 1 . 8

8/6/2019 h Holographic

8/17

Blu-ray Disc (also known as Blu-ray or BD) is an opticaldisc storage medium. Its main uses are high-definitionvideo and data storage. The disc has the same physicaldimensions as standard DVDs and CDs.

The name Blu-ray Disc is derived from the blue laser(violet-coloured) used to read and write this type ofdisc. Because of the beam's shorter wavelength (405nanometres), substantially more data can be stored ona Blu-ray Disc than on the DVD format, which uses a

red (650 nm) laser. A two-layer Blu-ray Disc can store50 gigabytes, almost six times the capacity of a two-layer DVD, or twelve and a half times that of a single-layer DVD.

8/6/2019 h Holographic

9/17

TYPE PHYSICALSTATE

SINGLE LAYERCAPACITY

DUAL LAYERCAPACITY

STANDARDDISC SIZE

12 cm, singlesided

25 GB 50 GB

MINI DISC SIZE 8 cm, single sided 7.8 GB 15.6 GB

8/6/2019 h Holographic

10/17

8/6/2019 h Holographic

11/17

Blu-ray Disc uses a BLUE (technically violet) laser operating at awavelength of 405 nm to read and write data. Conventional DVDsand CDs use red and near infrared lasers at 650 nm and 780 nmrespectively.

The blue-violet laser's shorter wavelength makes it possible to

store more information on a 12 cm CD/DVD sized disc. Theminimum "spot size" on which a laser can be focused is limited bydiffraction, and depends on the wavelength of the light and thenumerical aperture of the lens used to focus it. By decreasing thewavelength, increasing the numerical aperture from 0.60 to 0.85and making the cover layer thinner to avoid unwanted opticaleffects, the laser beam can be focused to a smaller spot. This

allows more information to be stored in the same area. For Blu-rayDisc, the spot size is 580 nm. In addition to the opticalimprovements, Blu-ray Discs feature improvements in dataencoding that further increase the capacity

8/6/2019 h Holographic

12/17

FOR

DRIVESPEED

DATARATE

WRITE TIME(MIN)

MB/S SL DL

.

2 2. 4

4 .4 2

8. 8

8 .8 8 4

2 .22 . 4

8 24.

2 2 . 4

FOR B -RAY

DRIVESPEED

DATARATE

WRITE TIME(MIN)

MB/S SL DL

4. 8

2 . 4

4 8 2 4

2

8 2 2

2 4 8

8/6/2019 h Holographic

13/17

8/6/2019 h Holographic

14/17

8/6/2019 h Holographic

15/17

1. Green writing/reading laser (532 nm)2. Red positioning/addressing laser (650 nm)

3. Hologram (data)4. Polycarbonate layer5. Photo polymeric layer (data-containing layer)6. Distance layers

7. Dichroic layer (reflecting green light)8. Aluminum reflective layer (reflecting red light)9. Transparent baseP. PIT

8/6/2019 h Holographic

16/17

THE OPTICAL STORAGE MEDIA IS ABETTR,SAFE,RELIABLE,FAST AND CHEAPWAY OF STORING DATA.

THEY HAVE TAKEN OVER THE MAGNETICSTORAGE FOR BACKING UP OF DATA AND

FUTURE PROSPECT OF STORING DATA INOPTICAL DEVICES IS VERY IMPRESSIVE

8/6/2019 h Holographic

17/17