26-04-2011, 12:20 PM
Submitted by
RAGHAVENDRA.S
[attachment=12822]
ABSTRACT
NRAM, short for nano-RAM or nanotube-based/nonvolatile random access memory, is a new memory storage technology owned by the company Nantero. The technology blends together tiny carbon nanotubes with conventional semiconductors. Because the memory-containing elements, nanotubes, are so small, NRAM technology will achieve very high memory densities: at least 10-100 times our current best. NRAM will operate electromechanically rather than just electrically, setting it apart from other memory technologies as a nonvolatile form of memory, meaning data will be retained even when the power is turned off. The creators of the technology claim it has the advantages of all the best memory technologies with none of the disadvantages, setting it up to be the universal medium for memory in the future.
Carbon nanotubes are small tubes of carbon atoms, only a few nanometers wide -- 1/100,000th the width of a human hair. The wall of a carbon nanotube is composed of a single carbon atom. Nanotubes are as rigid as diamond and conduct electricity as well as copper. In recent years, the cost of mass-producing nanotubes has plummeted.
By creating a thin "fabric" of nanotubes and arranging them in junctions on a silicon wafer embedded with conventional circuitry, a hybrid electro-mechanical memory system can be created. A nanotube configured in one position would indicate a 1, and in another position could indicate a 0. Manufacturing begins when a thin layer of nanotubes are spread across the surface of the wafer, then functionally unnecessary nanotubes are removed using conventional lithography techniques.
Currently the method of removing the unwanted nanotubes makes the system impractical. The accuracy and size of the epitaxial machinery is considerably "larger" that the cell size otherwise possible. Existing experimental cells have very low densities compared to existing systems; some new method of construction will have to be introduced in order to make the system practical.
INTRODUCTION
Today the world is of digital. All the electronic devices are formalized to manipulate the digital data. The back-bone of today’s research and development “The Computer” is also a digital device. Digital by name deals with digits and all the gadgets available today (like PDA’s, laptops, etc…) need to manipulate the digital data. To manipulate first we have to store it at a place. Thus MEMORY in today’s world plays a key role and a constant research to improve the memory in today’s electronic gadgets is ON.
RAM (random access memory) is the main storage device in all digital systems. The speed of the system mainly depends on how speed and vast the RAM is. Today with increasing power need of man even the POWER consumed is also a major part to look at. By generations RAM also had under gone many changes. Some of the versions of RAM’s which are in use are DRAM, SRAM and FLASH MEMORY. DRAM (dynamic RAM) although has a capability to hold large amounts of data it is slower and volatile.
SRAM (static RAM) even superior to DRAM in speed but less dense. Even this is volatile in nature. Overcoming the volatile nature of these two, FLASH MEMORY is the latest of today random access memories. Even this fails in power saving. Overcoming all these failures of above mentioned RAM’s , researchers developed a new RAM which unlike the semiconductor technology alone used by the former, uses a combination of NANOTECHNOLOGY and contemporary SEMICONDUCTOR TECHNOLOGY and is
given the name NRAM.
RAM (Random Access Memory):
It is a form of computer data storage. It takes the form of integrated circuits that allow stored volatile data to be accessed in random order. By contrast, storage devices such as magnetic discs and optical discs rely on the physical movement of the recording medium or a reading head. In these devices, the movement takes longer than data transfer, and the retrieval time varies based on the physical location of the next item.
The word RAM is often associated with volatile types of memory (such as DRAM memory modules), where the information is lost after the power is switched off. Many other types of memory are RAM too, including most types of ROM and a type of flash memory called NOR Flash.
Types of RAM: There are mainly two types of RAM
1. DRAM:
Dynamic RAM is the most common type of memory in use today. Inside a dynamic RAM chip, each memory cell holds one bit of information and is made up of two parts: a transistor and a capacitor. These are, of course, extremely small transistors and capacitors so that millions of them can fit on a single memory chip. The capacitor holds the bit of information -- a 0 or a 1. The transistor acts as a switch that lets the control circuitry on the memory chip read the capacitor or change its state.
A capacitor is like a small bucket that is able to store electrons. To store a 1 in the memory cell, the bucket is filled with electrons. To store a 0, it is emptied. The problem with the capacitor's bucket is that it has a leak. In a matter of a few milliseconds a full bucket becomes empty. Therefore, for dynamic memory to work, either the CPU or the memory controller has to come along and recharge all of the capacitors holding a 1 before they discharge. To do this, the memory controller reads the memory and then writes it right back. This refresh operation happens automatically thousands of times per second.
This refresh operation is where dynamic RAM gets its name. Dynamic RAM has to be dynamically refreshed all of the time or it forgets what it is holding. The downside of all of this refreshing is that it takes time and slows down the memory.
2. SRAM:
Static RAM uses a completely different technology. In static RAM, a form of flip-flop holds each bit of memory. A flip-flop for a memory cell takes 4 or 6 transistors along with some wiring, but never has to be refreshed. This makes static RAM significantly faster than dynamic RAM. However, because it has more parts, a static memory cell takes a lot more space on a chip than a dynamic memory cell. Therefore you get less memory per chip, and that makes static RAM a lot more expensive. So static RAM is fast and expensive, and dynamic RAM is less expensive and slower. Therefore static RAM is used to create the CPU's speed-sensitive cache, while dynamic RAM forms the larger system RAM space.
There are some other types of RAM:
There are many different types of RAM which have appeared over the years and it is often difficult knowing the difference between them both performance wise and visually identifying them. This article tells a little about each RAM type, what it looks like and how it performs.
1. FPM RAM
FPM RAM, which stands for Fast Page Mode RAM is a type of Dynamic RAM (DRAM). The term “Fast Page Mode comes from the capability of memory being able to access data that is on the same page and can be done with less latency. Most 486 and Pentium based systems from 1995 and earlier use FPM Memory.
FPM RAM
2.EDORAM
EDO RAM, which stands for “Extended Data Out RAM came out in 1995 as a new type of memory available for Pentium based systems. EDO is a modified form of FPM RAM which is commonly referred to as “Hyper Page Mode. Extended Data Out refers to fact that the data output drivers on the memory module are not switched off when the memory controller removes the column address to begin the next cycle, unlike FPM RAM. Most early Penitum based systems use EDO.
EDO RAM
3.SDRAM
SDRAM, which is short for Synchronous DRAM is a type of DRAM that runs in synchronization with the memory bus. Beginning in 1996 most Intel based chipsets began to support SDRAM which made it a popular choice for new systems in 2001.
SDRAM is capable of running at 133MHz which is about three times faster than FPM RAM and twice as fast as EDO RAM. Most Pentium or Celeron systems purchased in 1999 have SDRAM.
SD RAM
4.DDRRAM
DDR RAM, which stands for “Double Data Rate which is a type of SDRAM and appeared first on the market around 2001 but didn’t catch on until about 2001 when the mainstream motherboards started supporting it. The difference between SDRAM and DDR RAM is that instead of doubling the clock rate it transfers data twice per clock cycle which effectively doubles the data rate. DDRRAM has become mainstream in the graphics card market and has become the memory standard.
DDR RAM
Difference between DDR1, DDR2 & DDR3 types of RAM?
In computing, a computer bus operating with double data rate, transfers data on both the rising and falling edges of the clock signal. This is also known as double pumped and double transition.
DDR2 stores memory in memory cells that are activated with the use of a clock signal to synchronize their operation with an external data bus. Like DDR before it, DDR2 cells transfer data both on the rising and falling edge of the clock (a technique called "dual pumping"). The key difference between DDR and DDR2 is that in DDR2 the bus is clocked at twice the speed of the memory cells, so four words of data can be transferred per memory cell cycle.
DDR3 memory comes with a promise of a power consumption reduction of 30% compared to current commercial DDR2 modules due to DDR3's 1.5 V supply voltage, compared to DDR2's 1.8 V or DDR's 2.5 V. This supply voltage works well with the 90 nm fabrication technology used for most DDR3 chips. Some manufacturers further propose to use "dual-gate" transistors to reduce leakage of current.
The main benefit of DDR3 comes from the higher bandwidth made possible by DDR3's 8 bit deep pre-fetch buffer, whereas DDR2's is 4 bits, and DDR's is 2 bits deep.
RAGHAVENDRA.S
[attachment=12822]
ABSTRACT
NRAM, short for nano-RAM or nanotube-based/nonvolatile random access memory, is a new memory storage technology owned by the company Nantero. The technology blends together tiny carbon nanotubes with conventional semiconductors. Because the memory-containing elements, nanotubes, are so small, NRAM technology will achieve very high memory densities: at least 10-100 times our current best. NRAM will operate electromechanically rather than just electrically, setting it apart from other memory technologies as a nonvolatile form of memory, meaning data will be retained even when the power is turned off. The creators of the technology claim it has the advantages of all the best memory technologies with none of the disadvantages, setting it up to be the universal medium for memory in the future.
Carbon nanotubes are small tubes of carbon atoms, only a few nanometers wide -- 1/100,000th the width of a human hair. The wall of a carbon nanotube is composed of a single carbon atom. Nanotubes are as rigid as diamond and conduct electricity as well as copper. In recent years, the cost of mass-producing nanotubes has plummeted.
By creating a thin "fabric" of nanotubes and arranging them in junctions on a silicon wafer embedded with conventional circuitry, a hybrid electro-mechanical memory system can be created. A nanotube configured in one position would indicate a 1, and in another position could indicate a 0. Manufacturing begins when a thin layer of nanotubes are spread across the surface of the wafer, then functionally unnecessary nanotubes are removed using conventional lithography techniques.
Currently the method of removing the unwanted nanotubes makes the system impractical. The accuracy and size of the epitaxial machinery is considerably "larger" that the cell size otherwise possible. Existing experimental cells have very low densities compared to existing systems; some new method of construction will have to be introduced in order to make the system practical.
INTRODUCTION
Today the world is of digital. All the electronic devices are formalized to manipulate the digital data. The back-bone of today’s research and development “The Computer” is also a digital device. Digital by name deals with digits and all the gadgets available today (like PDA’s, laptops, etc…) need to manipulate the digital data. To manipulate first we have to store it at a place. Thus MEMORY in today’s world plays a key role and a constant research to improve the memory in today’s electronic gadgets is ON.
RAM (random access memory) is the main storage device in all digital systems. The speed of the system mainly depends on how speed and vast the RAM is. Today with increasing power need of man even the POWER consumed is also a major part to look at. By generations RAM also had under gone many changes. Some of the versions of RAM’s which are in use are DRAM, SRAM and FLASH MEMORY. DRAM (dynamic RAM) although has a capability to hold large amounts of data it is slower and volatile.
SRAM (static RAM) even superior to DRAM in speed but less dense. Even this is volatile in nature. Overcoming the volatile nature of these two, FLASH MEMORY is the latest of today random access memories. Even this fails in power saving. Overcoming all these failures of above mentioned RAM’s , researchers developed a new RAM which unlike the semiconductor technology alone used by the former, uses a combination of NANOTECHNOLOGY and contemporary SEMICONDUCTOR TECHNOLOGY and is
given the name NRAM.
RAM (Random Access Memory):
It is a form of computer data storage. It takes the form of integrated circuits that allow stored volatile data to be accessed in random order. By contrast, storage devices such as magnetic discs and optical discs rely on the physical movement of the recording medium or a reading head. In these devices, the movement takes longer than data transfer, and the retrieval time varies based on the physical location of the next item.
The word RAM is often associated with volatile types of memory (such as DRAM memory modules), where the information is lost after the power is switched off. Many other types of memory are RAM too, including most types of ROM and a type of flash memory called NOR Flash.
Types of RAM: There are mainly two types of RAM
1. DRAM:
Dynamic RAM is the most common type of memory in use today. Inside a dynamic RAM chip, each memory cell holds one bit of information and is made up of two parts: a transistor and a capacitor. These are, of course, extremely small transistors and capacitors so that millions of them can fit on a single memory chip. The capacitor holds the bit of information -- a 0 or a 1. The transistor acts as a switch that lets the control circuitry on the memory chip read the capacitor or change its state.
A capacitor is like a small bucket that is able to store electrons. To store a 1 in the memory cell, the bucket is filled with electrons. To store a 0, it is emptied. The problem with the capacitor's bucket is that it has a leak. In a matter of a few milliseconds a full bucket becomes empty. Therefore, for dynamic memory to work, either the CPU or the memory controller has to come along and recharge all of the capacitors holding a 1 before they discharge. To do this, the memory controller reads the memory and then writes it right back. This refresh operation happens automatically thousands of times per second.
This refresh operation is where dynamic RAM gets its name. Dynamic RAM has to be dynamically refreshed all of the time or it forgets what it is holding. The downside of all of this refreshing is that it takes time and slows down the memory.
2. SRAM:
Static RAM uses a completely different technology. In static RAM, a form of flip-flop holds each bit of memory. A flip-flop for a memory cell takes 4 or 6 transistors along with some wiring, but never has to be refreshed. This makes static RAM significantly faster than dynamic RAM. However, because it has more parts, a static memory cell takes a lot more space on a chip than a dynamic memory cell. Therefore you get less memory per chip, and that makes static RAM a lot more expensive. So static RAM is fast and expensive, and dynamic RAM is less expensive and slower. Therefore static RAM is used to create the CPU's speed-sensitive cache, while dynamic RAM forms the larger system RAM space.
There are some other types of RAM:
There are many different types of RAM which have appeared over the years and it is often difficult knowing the difference between them both performance wise and visually identifying them. This article tells a little about each RAM type, what it looks like and how it performs.
1. FPM RAM
FPM RAM, which stands for Fast Page Mode RAM is a type of Dynamic RAM (DRAM). The term “Fast Page Mode comes from the capability of memory being able to access data that is on the same page and can be done with less latency. Most 486 and Pentium based systems from 1995 and earlier use FPM Memory.
FPM RAM
2.EDORAM
EDO RAM, which stands for “Extended Data Out RAM came out in 1995 as a new type of memory available for Pentium based systems. EDO is a modified form of FPM RAM which is commonly referred to as “Hyper Page Mode. Extended Data Out refers to fact that the data output drivers on the memory module are not switched off when the memory controller removes the column address to begin the next cycle, unlike FPM RAM. Most early Penitum based systems use EDO.
EDO RAM
3.SDRAM
SDRAM, which is short for Synchronous DRAM is a type of DRAM that runs in synchronization with the memory bus. Beginning in 1996 most Intel based chipsets began to support SDRAM which made it a popular choice for new systems in 2001.
SDRAM is capable of running at 133MHz which is about three times faster than FPM RAM and twice as fast as EDO RAM. Most Pentium or Celeron systems purchased in 1999 have SDRAM.
SD RAM
4.DDRRAM
DDR RAM, which stands for “Double Data Rate which is a type of SDRAM and appeared first on the market around 2001 but didn’t catch on until about 2001 when the mainstream motherboards started supporting it. The difference between SDRAM and DDR RAM is that instead of doubling the clock rate it transfers data twice per clock cycle which effectively doubles the data rate. DDRRAM has become mainstream in the graphics card market and has become the memory standard.
DDR RAM
Difference between DDR1, DDR2 & DDR3 types of RAM?
In computing, a computer bus operating with double data rate, transfers data on both the rising and falling edges of the clock signal. This is also known as double pumped and double transition.
DDR2 stores memory in memory cells that are activated with the use of a clock signal to synchronize their operation with an external data bus. Like DDR before it, DDR2 cells transfer data both on the rising and falling edge of the clock (a technique called "dual pumping"). The key difference between DDR and DDR2 is that in DDR2 the bus is clocked at twice the speed of the memory cells, so four words of data can be transferred per memory cell cycle.
DDR3 memory comes with a promise of a power consumption reduction of 30% compared to current commercial DDR2 modules due to DDR3's 1.5 V supply voltage, compared to DDR2's 1.8 V or DDR's 2.5 V. This supply voltage works well with the 90 nm fabrication technology used for most DDR3 chips. Some manufacturers further propose to use "dual-gate" transistors to reduce leakage of current.
The main benefit of DDR3 comes from the higher bandwidth made possible by DDR3's 8 bit deep pre-fetch buffer, whereas DDR2's is 4 bits, and DDR's is 2 bits deep.
