Semiconductor Memory
Conventional memory device is understood as "semiconductor memory" and was fictional in 1968. It's supported technology referred to as the "semiconductor" that was fictional in 1947. several semiconductors sorted along is termed associate "integrated circuit", additional ordinarily referred to as a "computer chip". samples of semiconductor memory embrace read-only storage, RAM and nonvolatile storage. a giant advantage of pc RAM (main memory) is price; ram is cheap. the most disadvantage of RAM is volatility; after you flip your pc off, the contents of RAM area unit lost.
Molecular Memory
Molecular memory is that the name of a technology that uses organic molecules to store binary knowledge. The goblet of this technology would be to use one molecule to store one bit. For the close to future, it'd be additional realistic to expect to possess systems that use massive teams of molecules to represent one bit. differing kinds of molecules are researched, as well as macromolecule molecules. A additional precise name of a molecular memory system that uses macromolecule molecules is macromolecule Memory. alternative forms of molecular memory would have additional precise names derived from the kinds of molecules on that the technologies area unit based mostly.
Protein Memory
In the mid-1990s, the event of a protein-based memory system was the project of Henry Martyn Robert Birge - chemistry academician and director of the W.M. Keck Center for Molecular physics. He was aided by Jeff Stuart, a chemist and one in every of Birge's graduate students. The molecule in question is termed bacteriorhodospin. Purple in color, it exists within the organism halobacteria halobium that thrives in salt marshes wherever temperatures will reach 140F.
The macromolecule undergoes a molecular modification once subjected to lightweight creating it ideal for representing knowledge. every molecular modification is an element of a series of the many completely different states referred to as the photocycle. There area unit 3 main states: the bR state, the O state and therefore the letter state. The O state represents binary zero and therefore the letter state represents binary one whereas the bR or rest state is neutral. To survive the tough conditions of a salt marsh, the macromolecule should be improbably stable, a vital issue if it's to be used for representing knowledge.
While within the bR state, the macromolecule is placed during a clear vessel referred to as a cuvette, mensuration one x one x two inches. The cuvette is then crammed with a gel. The macromolecule is mounted in situ by the action of the gel. two arrays of optical devices - one red and one inexperienced - area unit wont to scan and write knowledge whereas a blue laser is employed for erasing.
Reading, Writing and Storage capability
We will begin within the bR state of the photocycle. a gaggle of molecules is targeted and hit by the inexperienced optical device array, conjointly referred to as the Paging lasers. These molecules area unit currently within the O state that represents binary zero. The O state permits for two attainable actions:
• Reading - through with the red optical device array set at low intensity
• Writing a binary one - through with the red optical device array set at high intensity that moves the molecules to the letter state
The letter state permits for two attainable actions:
• Reading - through with the red optical device array set at low intensity
• Erasing - through with the blue optical device that moves the molecules back to the bR state
A bacteriorhodospin storage system is slow. though molecules modification states in microseconds (millionths of a second), it's slow when put next to semiconductor memory that has associate time interval measured in nanoseconds. sadly, the time needed to really perform a scan or write is even bigger, on the order of 10 milliseconds (thousandths of a second). the info transfer rate on this kind of device is additionally terribly slow - ten MBps (MB per second). In theory, the one x one x two in. cuvette may hold one TB of knowledge or roughly one trillion bytes. In reality, Birge managed to store 800 MB and hoped to attain a capability of one.3 GB (billion bytes). The technology proven itself to the purpose that NASA was exploring strategies of rising the technology throughout space vehicle missions, that in truth resulted in higher storage densities.
Conclusion
Birge's quest to create a protein-based memory system for a PC was unsuccessful. though Birge's vision failing, the event of some style of molecular memory (possibly macromolecule memory) for desktop computers, looks attainable. Scientists have conjointly continued to figure on developing alternative concepts involving macromolecule memory. One plan from 2006 was to use a layer of bR proteins to the surface of DVDs to extend storage capability, in theory up to fifty TB (over fifty trillion bytes). A twin layer blu-ray disc encompasses a capability {of fifty|of fifty} GB (over 50 billion bytes).
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