Holographic memory

Holographic Memory
11/01/2017 1
By
Deependra Singh
CSE/27/13

Introduction
 Data storage has been a fundamental part of computing from
the beginning.
 currently dominated data storage methods are Optical data
storage and Magnetic data storage.
 In order to increase storage capabilities new Optical storage is
introduced called Holographic Memory.
 Holographic storage is capable of recording and reading millions of
bits in parallel, enabling data transfer rates greater than those
attained by traditional optical storage.
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What is Holographic Memory
 Holographic memory is a three-dimensional data storage
system that can store information at high density inside
the crystal or photopolymer.
 It is a memory that can store information in the form of
holographic image (hologram).
 It can store up to 1-4 TB of information in a sugar
cube sized crystal.
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History
 Holography is invented in 1947 by the Hungarian-British
physicist Dennis Gabor, who won a Nobel Prize for his
invention in 1971.
 Scientist Pieter J. Van Heerdan proposed the idea of
holographic memory in 1960s.
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Reasons for Developing
Holographic Storage
o Replacement as a backup media
• Higher data density than tape and current Hard
Drives
• Data is stable for an estimated 50 years without
degrading
• Faster read and write speeds
o Replacement for DVD
• Higher data density than Blu-Ray
• Faster read and write speeds
• Higher ceiling for max data storage capability
• Increasing resolutions for TVs will require more
storage for movies and games 11/01/2017 5

Holographic Versatile
Disk(HVDs)
1/17/2017 6
• These discs have the capacity to hold
up to 3.9 terabyte (TB) of information,
which is approximately 6,000 times the
capacity of a CD-ROM, 830 times the
capacity of a DVD, 160 times the
capacity of single-layer Blu-ray-Discs,
and about 8 times the capacity of
standard computer hard drives as of
2007.
• The HVD also has a transfer rate of 1
gigabyte/s

Components
Basic components that are needed to construct an HVD
system
 Blue-green argon laser
 Beam splitter to split the laser beam
 Mirrors to direct the laser beam
 Spatial light modulator (SLM)
 Lances to focus the laser beam
 Lithium-niobate crystal or photopolymer
 Charged coupled device camera (CCD)
11/01/2017 7

The HVD system: writing data
 When the blue-green argon laser is fired ,a beam
splitter creates two beams, a signal beam and a
reference beam.
 The signal beam passes through a SLM where digital
information, organized in a page(2-D plane) like
format of ones and zeroes, is modulated onto the
signal beam as a two dimensional pattern of
brightness and darkness.
 When the two beams intersect, the interference
pattern is created which stores the data carried by the
signal beam. The stored data is called hologram.
11/01/2017 8

The HVD system: reading data
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To retrieve data, the
reference beam is
focused on the
hologram at a
particular angle ;
this will retrieve the
modulated data
stored at the same
angle of interference
.

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1 Bit
Data
Surface
Recording
Layer
Substrate
Conventional Optical Disc
Page
Data
Volumetric
Recording
Layer
Page data are recorded into the
volumetric recording layer
in Holographic recording
HVD
~1μm
TM
Data are recorded on to the surface as
bit by bit
in CD/DVD System
Comparison

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Capacity: 700 mb Capacity: 30-50Gb
Capacity:1-4TBCapacity: 4.7Gb

Why has it taken so long to
develop an HDSS ?
• Lack of components
• Components that are supposed to be used were much
larger and more expensive
• For example
o Laser would have been 6 feet long
o LCDs were not developed until 1968
o CCD was not available until last decade
11/01/2017 13

Advantages
• Resistance to damage - If some parts of the medium are
damaged, all information can still be obtained from other
parts.
• Efficient retrieval - All information can be retrieved from
any part of the medium.
• Theoretical data storage of >1TB/cubic centimeter
oCurrent technology can store approximately 4TB on a DVD
sized disc(HVDs)
• Data longevity
11/01/2017 14

11/01/2017 15
•Data security
oWORM (Write-once read-many) prevents data
from being overwritten
• Faster Read/Write speeds
oData can be read and written in parallel instead of
linearly
oHigher speeds are necessary as storage amounts
increase

Limitations
• Not a guaranteed market leader
o If another technology becomes the industry standard
then read/write equipment will be hard to find
• Expensive development
o Existing technology is becoming better and cheaper
o It is difficult to market a product that is more
expensive per GB of storage.
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11/01/2017 17
APPLICATIONS
 A) Petaflop Computing
 B) Data Mining
 C) Future Computing System

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CONCLUSION
• In conclusion, Holographic Storage has the advantage
over other storage mediums as it relates to:
o Storage Capacity
o Transfer Rate
o Backup
• Its main disadvantage is its cost of ownership.
• Keep in mind, when Blu-ray was Introduced in 2006, a
25gigabyte disc cost nearly $1 a gigabyte. Its about half
the cost now. Overtime, the overall cost of holographic
data storage should decrease to an acceptable amount.

Holographic memory

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Holographic memory