Flash memory gets its name due to its microchip arrangement in such a way, that its section in memory cells gets erased in a single action or "Flash".
Both NOR and NAND Flash memory were invented from Dr. Fujio Masuoka from Toshiba in 1984. The name 'Flash' was suggested because the erasure process of this memory contents reminds a flash of a camera, and it's name was coined expressing how much faster it could be erased "in a flash". Dr. Masuoka presented the invention at the International Electron Devices Reaching (IEDM) held in San Jose, California in 1984 as well as Intel recognizes the potentiality of the invention and introduced the first commercial NOR type thumb chip in 1988, with long erase and create times.
Flash memory is a form of non-volatile memory that can be electrically erased and edit, which means that it does not need power to take care of the data stored in the particular chip. In addition, flash memory offers quick read access times together with better shock resistance than hard disks. These characteristics explain the actual popularity of flash memory for applications such as storage on battery-powered units.
Flash memory is loan from of EEPROM (Electrically-Erasable Programmable Read-Only Memory) that allows multiple memory locations to be erased or written in a single programming operation. Unlike an EPROM (Electrically Programmable Read-Only Memory) an EEPROM can be programmed and erased a variety of times electrically. Normal EEPROM only allows one location at a time to be erased or maybe written, meaning that flash will be able to operate at higher effective speeds when the systems using; it read and create to different locations at the same time.
Referring to the kind of logic gate used in each storage cell, Flash memory is built in two varieties together with named as, NOR flash and NAND flash.
Flash memory stores one bit of information in an array of transistors, called "cells", however recent flash memory products referred as multi-level cellular phone devices, can store more than 1 bit per cell depending on amount of electrons placed on the Floating Gate of the cell. NOR flash cell looks similar to semiconductor device like transistors, but it has two gates. First one is the control gate (CG) and the second one is a new floating gate (FG) that's shield or insulated in all directions by an oxide level. Because the FG is secluded by its screen oxide layer, electrons placed on it get trapped as well as data is stored throughout. On the other present NAND Flash uses tube injection for writing along with tunnel release for removing.
NOR flash that was developed by Intel in 1988 utilizing unique feature of long erase and write times and it is endurance of erase menstrual cycles ranges from 10, 000 to 100, 000 makes it ideal for storage of program code that needs to be infrequently updated, like in digital camera and PDAs. Though, later cards demand moved towards the cheaper NAND flash; NOR-based flash is hitherto the source of all the removable media.
Followed in 1989 Samsung and Toshiba form NAND flash with large density, lower cost per bit then NOR Whizz with faster erase and also write times, but this only allows sequence records access, not random such as NOR Flash, which makes NAND Flash suitable for mass storage device for example memory cards. SmartMedia was first NAND-based removable media and numerous others are right behind like MMC, Secure Digital, xD-Picture Cards and Storage Stick. Flash memory is frequently used to hold control code such as the basic input/output system (BIOS) inside a computer. When BIOS needs to be changed (rewritten), the flash memory can be written to in block rather than byte sizes, making it simple to update.
On the several other hand, flash memory is possibly not practical to random admittance memory (RAM) as RAM needs to be addressable at the byte (not typically the block) level. Thus, it is used more as a hard drive than as some sort of RAM. Because of this particular uniqueness, it is utilized with the help of specifically-designed file systems which extend writes over the media and deal with the long erase times from NOR flash blocks. JFFS was the first file systems, outdated by JFFS2. Then YAFFS was released in 2003, dealing specifically with NAND flash, and JFFS2 was updated to support NAND flash too. Still, in practice most comes after old FAT file product for compatibility purposes.
Although it can be read or write a byte at a time in a random accessibility fashion, limitation of expensive memory is, it must be erased a "block" at a time. Starting with a fresh erased block, any byte within that block can be programmed. However, once a byte has been programmed, it cannot be changed again until the entire block is deleted. In other words, flash memory (specifically NOR flash) offers random-access read and developing operations, but cannot provide random-access rewrite or wipe off operations.
This effect is moderately offset by some snack firmware or file system drivers by counting typically the writes and dynamically remapping the blocks in order to spread the write operations between the sectors, or by write verification and remapping to spare sectors in case of write failure.
Due to wear and tear on the insulating oxide layer around the charge storage mechanism, all types of flash memory erode after a certain number of erase functions ranging from 100, 000 to 1, 000, 000, but it can be read an unlimited number of times. Flash Card is comfortably rewritable memory and overwrites without warning with a high chance of data being overwritten and hence lost.
In spite of these clear advantages, worse may occur due to system failure, battery failure, accidental erasure, re-format, power surges, faulty electronics and corruption caused by hardware breakdown or software programs malfunctions; as a result your data could be lost and also damaged.
Flash Memory Data Recovery is the process of restoring facts from primary storage media when it can't be accessed normally. Flash memory data recovery is a flash memory file retrieval service that restores most corrupted and deleted photographs even if a memory card has been re-formatted. This can be due to physical damage or logical harm to the storage device. Data even from damage flash memory can be recovered, and more than 90% of lost data could be restored.
