Flash memory gets its name because of its chip layout in that section of its memory cells, eliminating a single action or "Flash".
Both NOR and NAND flash memory were presented by Dr. Fujio Masuoka invented by Toshiba in 1984.The name 'Flash' was suggested by the suppression of the memory contents reminds a flash of a camera and the name was coined to express the more could quickly be erased "in a moment." Dr. Masuoka presented the inventionInternational Electron Devices Meeting (IEDM) in San Jose, California, in 1984 and held Intel recognizes the potential for invention and commercial introduction of the first type of NOR flash chips 1988, with a long erase and write speed.
Flash memory is a form of nonvolatile memory that can be connected to erase and rewrite, the chip does not mean power to manage the data stored Moreover, the speed of flash memory read access times and betterShock resistance than hard disks. These characteristics explain the popularity of flash memory for storage applications, such as battery-powered devices.
Flash memory is possible by prior EEPROM (electrically erasable programmable read only memory), memory erased or overwritten in a programming operation. Unlike a programmed EPROM (Electrically Programmable Read Only Memory), EEPROM and removed multiple times electrically. Normal EEPROMhave a place at a time to delete or write, which means that the flash can be effective at higher speeds when the systems to work with him to read and write in different places simultaneously. is used to refer to the type of logic gate in each memory cell, the flash memory in two versions and the name, NOR flash and NAND Flash.
The flash memory stores one bit of information in an array of transistors, called "cells", but the flash memory cell last call at various levelsThe devices can store drew more than 1 bit per cell depending on the number of electrons in the floating gate of a cell. telephones, and the flash is similar to semiconductor device like transistors, but has two objectives. First, the control port (CG) and the second is a floating gate (FG) isolated on the plate or a layer of oxide. Since the FG oxide layer is quiet for his coat, sat trapped electrons and the data stored on them. On the other hand, NAND Flashuses tunnel injection for writing and tunnel release for erasing.
Intel NOR flash in 1988 to eliminate, as much for the write-once and clear and the cycles of development of resistance ranges suitable for storing program code, which is rarely updated 1-10000, such as digital cameras, PDAs. Although, later moved to the application of NAND flash memory cards cheaper NOR flash is now the source of all removable media. Followed in 1989Samsung and Toshiba NAND flash memory with higher density, lower cost per bit, and then with a fast and remove NOR Flash time to write, but only allows sequence data access, and not on a case such as flash memory NAND flash NOR is for mass storage cards.
SmartMedia is the first NAND removable media and many others are as originally MMC, Secure Digital, xD-Picture Card and Memory Stick. Flash memory is often used to maintain control of the code baseInput / Output System (BIOS) on a computer. If the BIOS needs to be changed (rewritten), the Flash memory in bytes to write, instead of block sizes, making it easy to update. On the other hand, flash memory is not practical, memory (RAM) addressable RAM requirements in terms of bytes (not block). Using more than one hard drive as memory.
Because of the particular specificity, it is written with the file system designed, use the extensionthrough the media and dealing with long hours to eliminate the NOR flash memory devices. JFFS file system was the first of jffs2 obsolete. Then yaffs was published in 2003, which was specifically with NAND flash and NAND flash jffs2 updated too. But in practice most follows old FAT file system for compatibility reasons.
Although you can read or write a byte at a time of random access, the limitation of flash memory, has a "block" be removed immediately. Onjust deleted the block, a byte can be programmed in this sentence. However, once a byte has been programmed, you can not change again until the entire block is erased. In other words, flash memory (NAND flash-specific) random access read and programming, but does not offer random-access rewrite or erase operations.
This effect is partially offset by a chip firmware or file system by counting the writes and dynamically reconfigure the block to compensateExtender write operations between sectors or write verification and reconfiguration of spare sectors typos.
The wear of the insulating oxide layer around the charge storage mechanism, to weaken all types of flash memory after deleting a number of functions in the range from 100,000 to 1,000,000, but can be considered unlimited in time .
Flash Card is easily rewritable memory and overwrites without warning with a high probability of data overwritten and lost.
Despite these obvious advantages, perhaps worse to come due to system failure, battery failure, accidental deletion, format, power surges, corruption and malfunctioning electronics due to a hardware or software could cause damage to data and losses.
Flash memory data recovery is the process of recovering data from primary storage media when you can not normally access. Flash Memory> Data Recovery is a flash memory file recovery, the damage and restores all deleted photos even if a memory card is formatted. This may be caused by physical damage or damage to the logical storage. Even data storage will be able to recover damages for Flash, and more than 90% of data loss can be restored.
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