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24-12-2010, 03:56 PM
flash ppt.pptx (Size: 202.33 KB / Downloads: 173)
Krishna Kumar Barik
Flash memory is a non-volatile computer storage that can be electrically erased and reprogrammed. It is a technology that is primarily used in Memory cards and USB flash drives for general storage and transfer of data between computers and other digital products.
Flash memory (both NOR and NAND types) was invented by Dr. Fujio Masuoka while working for Toshiba circa 1980. According to Toshiba, the name "flash" was suggested by Dr. Masuoka's colleague, Mr. Shoji Ariizumi, because the erasure process of the memory contents reminded him of the flash of a camera. Dr. Masuoka presented the invention at the IEEE 1984 International Electron Devices Meeting (IEDM) held in San Francisco, California.
Evolution Level of Flash Memory
Why Flash Memory Popular
Flash Rom storage devices are shock proof, dust proof, immune to magnetic fields and really small too.
Other Main Reason
Power consumption ,Portability ,Capacity
Durability ,Performance ,Reliability
Principle of operation
Flash memory stores information in an array of memory cells made from floating-gate transistors. In traditional single-level cell (SLC) devices, each cell stores only one bit of information. Some newer flash memory, known as multi-level cell (MLC) devices, can store more than one bit per cell by choosing between multiple levels of electrical charge to apply to the floating gates of its cells.
Flash memory circuit diagram
Basic Algorithm calling sequence
Flash memory type
Flash memory Architecture Decision:
Flash memory should be Removable or
Non-Removable .It is based on the requirement.
Flash memory is two type:
1. NOR gate Flash
2. NAND gate Flash
NOR gate Flash
In NOR gate flash, each cell has one end connected directly to ground, and the other end connected directly to a bit line.
This arrangement is called "NOR flash" because it acts like a NOR gate: when one of the word lines is brought high, the corresponding storage transistor acts to pull the output bit line low.
NOR Flash memory Architecture
NAND gate Flash
NAND flash also uses floating-gate transistors, but they are connected in a way that resembles a NAND gate: several transistors are connected in series, and only if all word lines are pulled high (transistors' VT) is the bit line pulled low. These groups are then connected via some additional transistors to a NOR-style bit line array.
NAND Flash Array
Distinction Between NOR and NAND Flash
Distinction Between NOR and NAND Flash:
The connections of the individual memory cells are different.
The interface provided for reading and writing the memory is different (NOR allows random-access for reading, NAND allows only page access).
Flash Memory has some draw back:
Flash memory is advanced computer storage.
Flash memory is non-volatile, no power is needed to maintain the information stored in the chip.
Flash memory offers fast read access times and better kinetic shock resistance than hard disks.
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26-02-2011, 10:36 AM
Flash.ppt (Size: 225.5 KB / Downloads: 166)
A type of EEPROM (Electrically-Erasable Programmable Read-Only Memory)
Non-volatile, solid state technology
Relatively limited lifespan
Information is stored in an array of memory cells made from floating-gate (FG) transistors
Packaged inside a memory card:
Can withstand intense pressure
Immersion in water
Better kinetic shock resistance than hard disks
Average power requirements range from 5V-12V
Flash Memory Cell
History of Flash Memory
Invented by Fujio Masuoka while he was working for Toshiba in the early 1980s
First introduced at the 1984 International Electron Devices Meeting in San Francisco
Manufacturers of Flash
NOR Flash Memory
Developed to replace read only memory
Full address and data buses allow random access to any memory location
Can access any memory cell
Slow sequential access
NAND Flash Memory
Developed to replace hard disks
Sequential-accessed command and data registers replace the external bus of NOR
Decreases chip real estate
Can only access pages
Faster sequential access
Counting writes & dynamically remapping blocks
Bad block management
Write verification and remapping bad sectors
Multi-Level Cell technology
Memory cells store more than one bit
Part of the reason for the success of Flash memory
Open NAND Flash Interface Working Group developed standard low-level interface
Standard command set for reading, writing, and erasing NAND flash chips
Mechanism for self-identification
Bit line replaced with embedded diffusion line to reduce cell size
Low power dissipation (3V)
DINOR (DIvided bit-line NOR) Flash
Attempts to reduce the chip real estate compared to conventional NOR
Low power dissipation (3V), sector erase, high data transfer rate
Future of Flash Memory
Continues to be among the most aggressively scaled electronic technologies
Memory cell size minimum of 20 nm expected to be met in 2010
May be replaced by Phase-Change RAM or other emerging technologies
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13-03-2012, 11:58 AM
to get information about the topic"flash memory" full report ppt and related topic refer the link bellow
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23-04-2012, 03:58 PM
MODEL -FARE_SEMINAR_REPORT.doc (Size: 931.5 KB / Downloads: 30)
The explosion of flash memory technology has dramatically increased storage capacity and decreased the cost of non-volatile semiconductor memory. The technology has fueled the proliferation of USB flash drives and is now poised to replace magnetic hard disks in some applications. A solid state drive (SSD) is a non-volatile memory system that emulates a magnetic hard disk drive (HDD). SSDs do not contain any moving parts, however, and depend on flash memory chips to store data. With proper design, an SSD is able to provide high data transfer rates, low access time, improved tolerance to shock and vibration, and reduced power consumption. For some applications, the improved performance and durability outweigh the higher cost of an SSD relative to an HDD.
FLOATING GATE FLASH MEMORY CELLS
SSDs mainly depend on flash memory chips to store data. The name "flash" was suggested because the process of erasing the memory contents reminded him of the flash of a camera. Flash memory chips store data in a large array of floating gate metal–oxide–semiconductor (MOS) transistors. Silicon wafers are manufactured with microscopic transistor dimension, now approaching 40 nanometers. In this flash memory thin insulating glass layers are necessary for proper operation of the memory cells. These layers are subjected to stressful temperatures and voltages, and their insulating properties deteriorate over time. Quite simply, flash memory can wear out.
SINGLE AND MULTIPLE LEVEL CELLS
The control gate voltage necessary to form the N-channel is controlled by the charge on the floating gate. The required voltage is called the gate threshold voltage and is labeled Vth. With SLC flash memory, there is only one programmed state in addition to the erased state. The total of two states allows a single data bit to be stored in the memory cell.
DISK DRIVE DEFINITIONS
• Hard disk drives (HDD) :
HDDs utilize ultra sophisticated magnetic recording and playback technologies. They are used as the primary data storage component technologies. component in notebooks, desktops, servers, and dedicated storage systems.
• Hybrid hard drives (HHD) :
HHDs are a new type of large buffer computer hard drive. They are different from standard hard drives in that they employ a large buffer (up up to 1GB) of nonvolatile flash memory used to cache data during normal use. By using this large buffer, the platters of the hard drive are at rest almost at all times, instead of constantly spinning as is the case in HDDs. This feature offers numerous benefits, such as decreased power consumption, improved reliability, and a faster boot process.
INTEL THIRD-GENERATION SSD 320SERIES
Intel announced today its highly anticipated third-generation solid-state drive (SSD) the Intel Solid-State Drive 320 Series. Based on its industry-leading 25-nanometer (nm) NAND flash memory, the Intel SSD 320 replaces and builds on its high-performing Intel X25-M SATA SSD. Delivering more performance and uniquely architected reliability features, the new Intel SSD 320 offers new higher capacity models, while taking advantage of cost benefits from its 25nm process with an up to 30 percent price reduction over its current generation.
As the Solid State Drives is a new innovative technology which will provide high data transference, high data security & enhanced reliability. And the most speculious highlighting feature is, the power consumption which can be contributed by the Intel third generation Solid State Drives with the help of the Intel 3-D Tri-Gate processors. Hence in the future the presence of cach memory can be avoided by using these Intel Third Generation Solid State Drives & also their main moto of the Intel organization is to cut energy use by 50% by the implementation of these Third Generation Solid State Drives.
Joined: Apr 2012
13-07-2012, 11:35 AM
FLASH MEMORY.pptx (Size: 339 KB / Downloads: 19)
Flash memory is a non-volatile computer storage chip.
Developed from electrically erasable programmable read only memory(EEPROM).
Has fast access time.
Faster than dynamic RAM.
But slower than static RAM.
Used in personal computers , digital audio player , digital cameras , scientific instruments , medical electronics , etc.
Principle of operation
Flash memory stores information in an array of memory cells made from floating-gate transistors.
In traditional single-level cell (SLC) devices, each cell stores only one bit of information.
Some newer flash memory, known as multi-level cell (MLC) devices, can store more than one bit per cell by choosing between multiple levels of electrical charge to apply to the floating gates of its cells.
In flash memory, each memory cell resembles a standard MOSFET ,except the transistor has two gates instead of one.
On top is the control gate (CG), as in other MOS transistors, but below this there is a floating gate (FG) insulated all around by an oxide layer. The FG is interposed between the CG and the MOSFET channel. Because the FG is electrically isolated by its insulating layer, any electrons placed on it are trapped there and, under normal conditions, will not discharge for many years.
Elevate the on-voltage applied to CG.
Electrons start flowing from source to drain.
With this source-to-drain flow some electrons have enough energy to penetrate the insulating layer around floating gate.