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Vimal Singh GIT. www.powerpointpresentationon.blogspot.com Introduction Basic Components Working Principle Applications & Conclusion Capacity: 700 mb Capacity: 4.7 Gb Capacity: 30-50 Gb Capacity: 1-4 Tb What is Holographic Memory ? • It is a memory that can store information in form of holographic image. • It is a technique that can store information at high density inside crystals or photopolymers. • It provides data to be written beneath the surface of the disc. • Holographic memory can store up to 1 Tb in a storage medium the size of a sugar cube crystal. Why do we need this ? • “For Internet applications alone, industry estimates are that storage needs are doubling every 100 days” • By the year 2010, a storage system serving an average LAN will need … 100 TB and a WAN server will require 10TB to 1 petabyte …of storage” (Red Herring) Basic Components spatial light modulator LCD panel To direct the laser beams To spilt the laser beam photopolymer Lithiumniobate crystal Mirrors Beam splitters CCD camera Blue-green argon laser Interprets the digital information Working Principle Continues.. Creating Holograms Pattern left on media Reconstructing the image Shift Characteristics Read-out Shift: Page Data Y X 1μm pitch 1μm Shift multiplexing read/write can be done at 3μpitch 2μm 3μm Properties of Hologram •A block or sheet of photosensitive material which records the diffraction of two light sources. •A laser beam is splatted into two beams: Source beam Reference beam •The two beams diffracts to form the image on the recording medium Spatial light modulator •It is used for creating binary information out of laser light. •It is a 2D plane, consisting of pixels which can be turned on and off to create binary 1.s and 0.s. •It contains a two-dimensional array of windows, which are only microns wide. Page Data Access •As the data is stored in the form of holograms, data retrieval must be in the same form. •So, a holographic system sends data in the form of pages. •It provides fast access times. Error Correction •As the density of data is massive, it is prone to errors. •Errors can be controlled by: o Recording errors o Page level parity bits o Interfacing Recording Errors •Cause: Noise generated by laser beam •Result: Can change a binary 0 to binary 1 •Possible Solution: Improvement in laser beam and recording material Page-level Parity Bits •Data is stored in the form of 2-D array •Odd no. of bits accounts for parity 1 •Even no. of bits accounts for parity 0 •Parity check bits are used to identify any errors present in the array Interfacing •While reading the data, they are sent to the computer as sheets. •Such thing may exceed the processor throughput •Remedy: Defining set of rules which can be used for correction and reading of data efficiently. Applications 1 Data Mining 2 Petaflop Computing 3 Future Computer Systems 4 Conclusion • Built on technology that’s around for 40+ years • Holographic Memory is the future of data storage o HUGE capacity, Very fast, Smaller o Parallel processing • Current storage methods nearing there fundamental limits of storage density • Large market and little new competition