19-07-2011, 10:39 AM
Submitted by
SANAL S
[attachment=14613]
Abstract
While magnetic and semi-conductor based information storage devices have been in use since the middle 1950's, today's computers and volumes of information require increasingly more efficient and faster methods of storing data. While the speed of integrated circuit random access memory (RAM) has increased steadily over the past ten to fifteen years, the limits of these systems are rapidly approaching. In response to the rapidly changing face of computing and demand for
• physically smaller,
• greater capacity,
• bandwidth,
A number of alternative methods to integrated circuit information storage have surfaced recently. Among the most promising of the new alternatives are
• photopolymer- based devices,
• holographic optical memory storage devices, and
• protein-based optical memory storage using rhodopsin ,
• Photosynthetic reaction centers, cytochrome c, photosystems I and II,
phycobiliproteins, and phytochrome.
This article focuses mainly on protein-based optical memory storage using the photosensitive protein bacteriorhodopsin with the two-photon method of exciting the molecules, but briefly describes what is involved in the other two. Bacteriorhodopsin is a light-harvesting protein from bacteria that live in salt marshes that has shown some promise as feasible optical data storage. The current work is to hybridize this biological molecule with the solid state components of a typical computer.
Protein Based Optical Memory
1. Introduction
Since the dawn of time, man has tried to record important events and techniques for everyday life. At first, it was sufficient to paint on the family cave wall how one
hunted. Then came the people who invented spoken languages and the need arose to
record what one was saying without hearing it firsthand. Therefore, years later, earlier
scholars invented writing to convey what was being said. Pictures gave way to letters
which represented spoken sounds. Eventually clay tablets gave way to parchment,
which gave way to paper. Paper was, and still is, the main way people convey
information. However, in the mid twentieth century computers began to come into
general use . . .
Computers have gone through their own evolution in storage media. In the forties, fifties, and sixties, everyone who took a computer course used punched cards
to give the computer information and store data. In 1956, researchers at IBM developed the first disk storage system. This was called RAMAC (Random Access
Method of Accounting and Control) .
Since the days of punch cards, computer manufacturers have strived to squeeze more data into smaller spaces. That mission has produced both competing and complementary data storage technology including electronic circuits, magnetic media like hard disks and tape, and optical media such as compact disks.
Today, companies constantly push the limits of these technologies to improve their speed, reliability, and throughput -- all while reducing cost. The fastest and most expensive storage technology today is based on electronic storage in a circuit such as a solid state "disk drive" or flash RAM. This technology is getting faster and is able to
store more information thanks to improved circuit manufacturing techniques that
shrink the sizes of the chip features. Plans are underway for putting up to a gigabyte
of data onto a single chip.
Magnetic storage technologies used for most computer hard disks are the most
common and provide the best value for fast access to a large storage space. At the low
end, disk drives cost as little as 25 cents per megabyte and provide access time to data
in ten milliseconds. Drives can be ganged to improve reliability or throughput in a
Redundant Array of Inexpensive Disks (RAID). Magnetic tape is somewhat slower
than disk, but it is significantly cheaper per megabyte. At the high end, manufacturers
are starting to ship tapes that hold 40 gigabytes of data. These can be arrayed together
into a Redundant Array of Inexpensive Tapes (RAIT), if the throughput needs to be
increased beyond the capability of one drive.
For randomly accessible removable storage, manufacturers are beginning to
ship low-cost cartridges that combine the speed and random access of a hard drive
with the low cost of tape. These drives can store from 100 megabytes to more than
one gigabyte per cartridge.
Standard compact disks are also gaining a reputation as an incredibly cheap
way of delivering data to desktops. They are the cheapest distribution medium around
when purchased in large quantities ($1 per 650 megabyte disk). This explains why so
much software is sold on CD-ROM today. With desktop CD-ROM recorders, individuals are able to publish their own CD-ROMs.
With existing methods fast approaching their limits, it is no wonder that a
number of new storage technologies are developing. Currently, researches are looking
at protien-based memory to compete with the speed of electronic memory, the
reliability of magnetic hard-disks, and the capacities of optical/magnetic storage. We
contend that three-dimensional optical memory devices made from bacteriorhodopsin
utilizing the two photon read and write-method is such a technology with which the
future of memory lies.
In a prototype memory system, bacteriorhodopsin stores data in a 3-D matrix.
The matrix can be build by placing the protein into a cuvette (a transparent vessel)
filled with a polyacrylamide gel. The protein, which is in the bR state, gets fixed in by
the polymerization of the gel. A battery of Krypton lasers and a charge-injection
device (CID) array surround the cuvette and are used to write and read data. While a molecule changes states within microseconds, the combined steps to read or write operation take about 10 milliseconds. However like the holographic storage, this device obtains data pages in parallel, so a 10 Mbps is possible. This speed is similar to that of slow semiconductor memory.
2. Memory Research and Development
Semiconductor memories were first developed in 1958 by Jack St. Clair Kilby
was revolutionary for that era but this technology is already showing its age. As the
millennium nears, research into memory technologies is expanding into new
previously unexplored areas for digital storage solutions. These new fields promise to
fulfill the data processing and computational needs of the 21st century. The primary
forms of memory which are currently being explored are optical memory and molecular memory. One of the reasons why the need for new technologies has arisen
is that the design and construction of smaller and smaller chips is becoming increasingly difficult. Manufacturers are working with dies in the .18 - .25 micron range. This will decrease even more but there is a finite limit to how far you can reduce the die sizes. The restrictions are twofold. One restriction is simply economic.
The cost of producing smaller chips is skyrocketing. More importantly though the
laws of physics will eventually halt this progression of decreasing dies. Moore's law
states that the number of transistors on a chip will double approximately even 18
months and this has held true ever since he made his prediction in the 1960s.
Semiconductor chips are manufactured using a process known as
photolithography where the desired circuit features are mapped onto the silicon via a
mask and a light source. The problem arises though that your light source must be at
least as small as the features you're trying to fashion. This becomes increasingly
difficult as the wavelengths of the spectrum are fixed and will not change. Krypton-
Fluoride ultraviolet laser light is currently being used as the light source for .25
micron mask operations and although the masks can still be smaller, the task becomes
increasingly complex. One developmental system which seeks to overcome these
limitations is optical computing.
Optical computing relies on photons rather than electrons for data transfer.
Electrons although fast have mass and are limited in velocity. Photons on the other hand are based on light waves are as such have no mass are travel at the speed of
light. The process of using light to store data is known as holography. Holographic
data storage reads and writes entire blocks in a single operation making it extremely
fast as a storage medium. The parallel nature of the data access means that speeds of
up to 1 Gbps can be achieved and storage densities of 10 GB per cubic centimetre are
capable. Polymer memory cubes exist which allow data to be stored and accessed in
three dimensions making it very fast for optical storage. Another advantage is that the
photons in the optical computer are not subject to electrical or magnetic interference
as are their electronic counterparts. Building a system around photonics isn't as easy
as it sounds though and many years of research and development will be needed
before a successful system can be built. Several groups are working on such a system
though. Researchers from TRW Space Technology Group, the University of
California-Berkley, the National Institute of Standards and Technology, Hewlett-
Package Research Division and Stanford University are all working together in order
to develop a digital computer system based on photonics. One of the difficulties
which arise in building such a machine is that it is much more difficult to construct
hardware which can control the photons. A second alternative to traditional storage
mediums is molecular memory. At first this approach might seem somewhat odd and
possibly insane. However some of the greatest scientific minds in history were
considered insane at the time.
Professor R obert Birge has developed a system to represent binary data using a
protein known as bacteriorhodopsin. One might question why proteins would be used
to store data. Size in general allows proteins to be a good candidate for data storage
and the bacteriorhodopsin was chosen because its sensitivity to light allows it to
change structurally and would be a good representation of a logic gate, the primary
building block of our memor y cell. A series of lasers is then used to excite the protein
molecules and read or set their states. Currently speeds of 10 Mbps can be achieved
however Professor Birge is convinced that 80 Mbps can be reached. So currently
molecular memor y isn't very fast in comparison to semiconductor memories but its
advantages lie is the cost of developments, storage density, and its non-volatility
SANAL S
[attachment=14613]
Abstract
While magnetic and semi-conductor based information storage devices have been in use since the middle 1950's, today's computers and volumes of information require increasingly more efficient and faster methods of storing data. While the speed of integrated circuit random access memory (RAM) has increased steadily over the past ten to fifteen years, the limits of these systems are rapidly approaching. In response to the rapidly changing face of computing and demand for
• physically smaller,
• greater capacity,
• bandwidth,
A number of alternative methods to integrated circuit information storage have surfaced recently. Among the most promising of the new alternatives are
• photopolymer- based devices,
• holographic optical memory storage devices, and
• protein-based optical memory storage using rhodopsin ,
• Photosynthetic reaction centers, cytochrome c, photosystems I and II,
phycobiliproteins, and phytochrome.
This article focuses mainly on protein-based optical memory storage using the photosensitive protein bacteriorhodopsin with the two-photon method of exciting the molecules, but briefly describes what is involved in the other two. Bacteriorhodopsin is a light-harvesting protein from bacteria that live in salt marshes that has shown some promise as feasible optical data storage. The current work is to hybridize this biological molecule with the solid state components of a typical computer.
Protein Based Optical Memory
1. Introduction
Since the dawn of time, man has tried to record important events and techniques for everyday life. At first, it was sufficient to paint on the family cave wall how one
hunted. Then came the people who invented spoken languages and the need arose to
record what one was saying without hearing it firsthand. Therefore, years later, earlier
scholars invented writing to convey what was being said. Pictures gave way to letters
which represented spoken sounds. Eventually clay tablets gave way to parchment,
which gave way to paper. Paper was, and still is, the main way people convey
information. However, in the mid twentieth century computers began to come into
general use . . .
Computers have gone through their own evolution in storage media. In the forties, fifties, and sixties, everyone who took a computer course used punched cards
to give the computer information and store data. In 1956, researchers at IBM developed the first disk storage system. This was called RAMAC (Random Access
Method of Accounting and Control) .
Since the days of punch cards, computer manufacturers have strived to squeeze more data into smaller spaces. That mission has produced both competing and complementary data storage technology including electronic circuits, magnetic media like hard disks and tape, and optical media such as compact disks.
Today, companies constantly push the limits of these technologies to improve their speed, reliability, and throughput -- all while reducing cost. The fastest and most expensive storage technology today is based on electronic storage in a circuit such as a solid state "disk drive" or flash RAM. This technology is getting faster and is able to
store more information thanks to improved circuit manufacturing techniques that
shrink the sizes of the chip features. Plans are underway for putting up to a gigabyte
of data onto a single chip.
Magnetic storage technologies used for most computer hard disks are the most
common and provide the best value for fast access to a large storage space. At the low
end, disk drives cost as little as 25 cents per megabyte and provide access time to data
in ten milliseconds. Drives can be ganged to improve reliability or throughput in a
Redundant Array of Inexpensive Disks (RAID). Magnetic tape is somewhat slower
than disk, but it is significantly cheaper per megabyte. At the high end, manufacturers
are starting to ship tapes that hold 40 gigabytes of data. These can be arrayed together
into a Redundant Array of Inexpensive Tapes (RAIT), if the throughput needs to be
increased beyond the capability of one drive.
For randomly accessible removable storage, manufacturers are beginning to
ship low-cost cartridges that combine the speed and random access of a hard drive
with the low cost of tape. These drives can store from 100 megabytes to more than
one gigabyte per cartridge.
Standard compact disks are also gaining a reputation as an incredibly cheap
way of delivering data to desktops. They are the cheapest distribution medium around
when purchased in large quantities ($1 per 650 megabyte disk). This explains why so
much software is sold on CD-ROM today. With desktop CD-ROM recorders, individuals are able to publish their own CD-ROMs.
With existing methods fast approaching their limits, it is no wonder that a
number of new storage technologies are developing. Currently, researches are looking
at protien-based memory to compete with the speed of electronic memory, the
reliability of magnetic hard-disks, and the capacities of optical/magnetic storage. We
contend that three-dimensional optical memory devices made from bacteriorhodopsin
utilizing the two photon read and write-method is such a technology with which the
future of memory lies.
In a prototype memory system, bacteriorhodopsin stores data in a 3-D matrix.
The matrix can be build by placing the protein into a cuvette (a transparent vessel)
filled with a polyacrylamide gel. The protein, which is in the bR state, gets fixed in by
the polymerization of the gel. A battery of Krypton lasers and a charge-injection
device (CID) array surround the cuvette and are used to write and read data. While a molecule changes states within microseconds, the combined steps to read or write operation take about 10 milliseconds. However like the holographic storage, this device obtains data pages in parallel, so a 10 Mbps is possible. This speed is similar to that of slow semiconductor memory.
2. Memory Research and Development
Semiconductor memories were first developed in 1958 by Jack St. Clair Kilby
was revolutionary for that era but this technology is already showing its age. As the
millennium nears, research into memory technologies is expanding into new
previously unexplored areas for digital storage solutions. These new fields promise to
fulfill the data processing and computational needs of the 21st century. The primary
forms of memory which are currently being explored are optical memory and molecular memory. One of the reasons why the need for new technologies has arisen
is that the design and construction of smaller and smaller chips is becoming increasingly difficult. Manufacturers are working with dies in the .18 - .25 micron range. This will decrease even more but there is a finite limit to how far you can reduce the die sizes. The restrictions are twofold. One restriction is simply economic.
The cost of producing smaller chips is skyrocketing. More importantly though the
laws of physics will eventually halt this progression of decreasing dies. Moore's law
states that the number of transistors on a chip will double approximately even 18
months and this has held true ever since he made his prediction in the 1960s.
Semiconductor chips are manufactured using a process known as
photolithography where the desired circuit features are mapped onto the silicon via a
mask and a light source. The problem arises though that your light source must be at
least as small as the features you're trying to fashion. This becomes increasingly
difficult as the wavelengths of the spectrum are fixed and will not change. Krypton-
Fluoride ultraviolet laser light is currently being used as the light source for .25
micron mask operations and although the masks can still be smaller, the task becomes
increasingly complex. One developmental system which seeks to overcome these
limitations is optical computing.
Optical computing relies on photons rather than electrons for data transfer.
Electrons although fast have mass and are limited in velocity. Photons on the other hand are based on light waves are as such have no mass are travel at the speed of
light. The process of using light to store data is known as holography. Holographic
data storage reads and writes entire blocks in a single operation making it extremely
fast as a storage medium. The parallel nature of the data access means that speeds of
up to 1 Gbps can be achieved and storage densities of 10 GB per cubic centimetre are
capable. Polymer memory cubes exist which allow data to be stored and accessed in
three dimensions making it very fast for optical storage. Another advantage is that the
photons in the optical computer are not subject to electrical or magnetic interference
as are their electronic counterparts. Building a system around photonics isn't as easy
as it sounds though and many years of research and development will be needed
before a successful system can be built. Several groups are working on such a system
though. Researchers from TRW Space Technology Group, the University of
California-Berkley, the National Institute of Standards and Technology, Hewlett-
Package Research Division and Stanford University are all working together in order
to develop a digital computer system based on photonics. One of the difficulties
which arise in building such a machine is that it is much more difficult to construct
hardware which can control the photons. A second alternative to traditional storage
mediums is molecular memory. At first this approach might seem somewhat odd and
possibly insane. However some of the greatest scientific minds in history were
considered insane at the time.
Professor R obert Birge has developed a system to represent binary data using a
protein known as bacteriorhodopsin. One might question why proteins would be used
to store data. Size in general allows proteins to be a good candidate for data storage
and the bacteriorhodopsin was chosen because its sensitivity to light allows it to
change structurally and would be a good representation of a logic gate, the primary
building block of our memor y cell. A series of lasers is then used to excite the protein
molecules and read or set their states. Currently speeds of 10 Mbps can be achieved
however Professor Birge is convinced that 80 Mbps can be reached. So currently
molecular memor y isn't very fast in comparison to semiconductor memories but its
advantages lie is the cost of developments, storage density, and its non-volatility
