Semiconductor memory
Conventional computer memory is known as “semiconductor memory” and was invented in 1968. It is based on a technology known as “semiconductor” that was invented in 1947. Many grouped semiconductors are called “integrated circuit”, more commonly known as “Chip computer “. Examples of semiconductor memory include ROM, RAM, and flash memory. One big advantage of computer RAM (main memory) is price; ram is thoughtless. The main disadvantage of RAM is volatility; When you turn off your computer, the contents of RAM are lost.
Molecular memory
Molecular memory is the name of a technology that uses organic molecules to store binary data. The Holy Grail of this technology would be to use a molecule to store one bit. In the near future, it would be more realistic to expect to have systems that use large groups of molecules to represent a single bit. Different types of molecules have been investigated, including protein molecules. A more accurate name for a molecular memory system that uses protein molecules is Protein Memory. Other types of molecular memory would have more precise names derived from the types of molecules on which the technologies are based.
Protein memory
In the mid-1990s, the development of a protein-based memory system was the project of Robert Birge, professor of chemistry and director of the WM Keck Center for Molecular Electronics. He was assisted by Jeff Stuart, a biochemist and one of Birge’s graduate students. The protein molecule in question is called bacteriorhodospin. Purple in color, it exists in the microorganism halobacterium halobium that thrives in salt marshes where temperatures can reach 140 ° F.
The protein undergoes a molecular change when exposed to light, making it ideal for rendering data. Each molecular change is part of a series of many different states known as a photocycle. There are three main states: the bR state, the O state, and the Q state. The O state represents binary 0 and the Q state represents binary 1, while the bR or rest state is neutral. To survive the harsh conditions of a marsh, the protein must be incredibly stable, a critical factor if it is to be used to represent data.
While in the bR state, the protein is placed in a clear container called a cuvette, which measures 1 x 1 x 2 inches. Then the cuvette is filled with a gel. The protein is fixed in place by gel solidification. 2 laser arrays, one red and one green, are used to read and write data, while a blue laser is used to erase.
Read, write and store capacity
We will start in the bR state of the photocycle. A group of molecules is targeted and hit by the green laser array, also known as targeting lasers. These molecules are now in the O state which represents the binary 0. The O state allows 2 possible actions:
• Reading: performed with the red laser matrix set to low intensity
• Write a binary 1: made with the red laser matrix set at high intensity that moves the molecules to the Q state
The Q state allows 2 possible actions:
• Reading: performed with the red laser matrix set to low intensity
• Erasing: done with the blue laser that returns the molecules to the bR state
A bacteriorhodospin storage system is slow. Although molecules change state in microseconds (millionths of a second), it is slow compared to semiconductor memory, which has an access time measured in nanoseconds. Unfortunately, the time required to perform a read or write is even longer, on the order of ten milliseconds (thousandths of a second). The data transfer speed in this type of storage device is also very slow: 10 MBps (MB per second). In theory, the 1 x 1 x 2-inch bucket could hold 1 TB of data or roughly a trillion bytes. Birge actually managed to store 800MB and expected to reach a capacity of 1.3GB (1 billion bytes). The technology was proven to the point that NASA was exploring methods to improve the technology during space shuttle missions, which in fact resulted in higher storage densities.
conclusion
Birge’s quest to build a protein-based memory system for a desktop computer was unsuccessful. Although Birge’s vision failed, the development of some form of molecular memory (possibly protein memory) for desktop computers seems possible. Scientists have also continued to develop other ideas related to protein memory. One idea from 2006 was to apply a layer of bR proteins to the surface of DVDs to increase storage capacity, theoretically up to 50TB (more than 50 trillion bytes). A double-layer blu-ray disc has a capacity of 50 GB (more than 50 billion bytes).