ABDULLA RASHARI M K COMPUTER SCIENCE DEPTSRINIVAS INSTITUTE OF TECHNOLOGY,MANGALORE
Outline Introduction What is HVD? Basics of Holographic memory Technology used in HVD Structure of HVD Writing data Reading data Advantages, disadvantages and applications of HVD Facts Future Aspects Conclusion Reference
Introduction HVD is an advanced optical disk that‟s presently in the development stage. Storage capacity :- 1 terabyte (TB). Data transfer rate :- 1 Gigabit per second. The technology permits over 10 kilobits of data to be written and read in parallel with a single flash.
Introduction An HVD would be a successor to today‟s Blu-ray and HD-DVD technologies. Advancements in the technology were made, in the early 21st century. Developed by the “Holography Storage Development Forum”. HVD can store up to 60 times the data of a regular DVD and it can read and write data 10 times faster as well.
What is HVD ? Definition:- Holographic versatile disc is a holographic storage format that looks like a DVD but is capable of storing far more data. Prototype HVD devices have been created with a capacity of 3.9 terabytes (TB) and a transfer rate of 1 Gbps. 1 HVD = 5,500 CD-ROMs = 830 DVDs = 160 Blu- ray discs Uses laser beams to store data in 3D.
Basics of Holographic Memory Holography is a method of recording patterns of light to produce a 3D object. The recorded patterns of light are called a hologram. Creation of a hologram begins with a focused beam of light, a laser. Laser splits up into 2 :- Reference beam Information beam
Technology used in HVD Collinear holography – The laser beams are collimated. Blue-green laser reads the data encoded in the form of laserinterference. Red laser serves the purpose of reference beam and to read the servo info.
Structure of HVD The Holographic Versatile Disc structure consists of the following components: Green writing/reading laser Red positioning/addressing laser Hologram (data) Polycarbon layer Photopolymeric layer (data-containing layer) Distance layers Dichroic layer (reflecting green light) Aluminum reflective layer (reflecting red light) Transparent base
Writing data A simplified HVD system consists of the following main components: Blue or green laser (532-nm wavelength in the test system) Beam splitter/merger Mirrors Spatial light modulator (SLM) CMOS sensor Photopolymer recording medium
Writing data Information is encoded into binary and is stored in the SLM. These data are turned into ones and zeroes represented as opaque or translucent areas on a „page‟. When the information beam passes through the SLM, portions of the light are blocked by the opaque areas of the page, and portions pass through the translucent areas. When the reference beam and the information beam rejoin on the same axis, they create a pattern of light interference - the holography data.
Writing data Page Data Hologram made from the Page Data
Reading data To read, we‟ve to retrieve the light pattern stored in the hologram. Laser is projected onto the hologram – a light beam that is identical to the reference beam . The hologram diffracts this beam according to the specific pattern of light interference its storing. The resulting light recreates the image of the page data that established the light-interference pattern – Reconstruction beam. The reconstruction beam - bounces back off the disc, it travels to the CMOS sensor. The CMOS sensor then reproduces the page data.
Advantages, disadvantages of HVD Advantages :- More storage. Reads and writes quickly. Price, expected to be slashed down. Disadvantages :- Initial price of the player and disc are high. Price and storage not confirmed, still in R&D.
Applications of HVD Applications:- Used for storing large amounts of data most likely for large companies. Could be the most efficient way to backup information in the near future.
Facts It has been estimated that the books in the U.S. Library of Congress, the largest library in the world , could be stored on six HVDs. The pictures of every landmass on Earth - like the ones shown in Google Earth - can be stored on two HVDs. With MPEG4 ASP encoding, a HVD can hold anywhere between 4,600-11,900 hours of video, which is enough for non-stop playing for a year.
Future aspects Have tremendous implications in the commercial, industrial and d-Cinema realms. Will find wide use for backing up and archiving the media libraries, including the one at the Hollywood studios.
Conclusion Materialized with the evolution of the collinear holography technology. Stores far more data than, what a DVD can. Prototype HVD has a capacity of 3.9 TB and a transfer rate of 1 Gbps. Hence, 1 HVD = 830 DVDs = 160 Blu-Ray discs.
Reference . Hideyoshi Horimai and Y.Aoki, “Holographic versatile disc(HVD) System” . Optical data storage Topical Meeting 2006, 2006page(s):6-8. [3.] Hideyoshi Horimai and Xiaodi Tan,“Holographic Information Storage System: . Today and Future,” Magnetics,IEEETransactions on Volume 43/Issue2,part 2 feb2007, page(s):943-947. . G. Deepika, “Holographic versatile disc”http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5738819&isnumber =5738811 . http://electronics.howstuffworks.com/hvd.htm . http://electronics.howstuffworks.com/hvd1.htm . http://electronics.howstuffworks.com/hvd2.htm . http://electronics.howstuffworks.com/hvd3.htm . http://en.wikipedia.org/wiki/Holographic_Versatile_Disc