Flash memory Wikipedia. For the neuropsychological concept related to human memory, see flashbulb memory. This article needs to be updated. Please update this article to reflect recent events or newly available information. October 2. Flash memory is an electronic solid state non volatilecomputer storage medium that can be electrically erased and reprogrammed. Toshiba developed flash memory from EEPROM electrically erasable programmable read only memory in the early 1. The two main types of flash memory are named after the NAND and NORlogic gates. The individual flash memory cells exhibit internal characteristics similar to those of the corresponding gates. D0Bvw.jpg' alt='Flash Serial Number Macbook Pro' title='Flash Serial Number Macbook Pro' />While EPROMs had to be completely erased before being rewritten, NAND type flash memory may be written and read in blocks or pages which are generally much smaller than the entire device. NOR type flash allows a single machine word byte to be written  to an erased location  or read independently. The NAND type operates primarily in memory cards, USB flash drives, solid state drives those produced in 2. NAND or NOR flash memory is also often used to store configuration data in numerous digital products, a task previously made possible by EEPROM or battery powered static RAM. One key disadvantage of flash memory is that it can only endure a relatively small number of write cycles in a specific block. Example applications of both types of flash memory include personal computers, PDAs, digital audio players, digital cameras, mobile phones, synthesizers, video games, scientific instrumentation, industrial robotics, and medical electronics. In addition to being non volatile, flash memory offers fast read access times, although not as fast as static RAM or ROM. Its mechanical shock resistance helps explain its popularity over hard disks in portable devices, as does its high durability, ability to withstand high pressure, temperature and immersion in water, etc. Although flash memory is technically a type of EEPROM, the term EEPROM is generally used to refer specifically to non flash EEPROM which is erasable in small blocks, typically bytes. Because erase cycles are slow, the large block sizes used in flash memory erasing give it a significant speed advantage over non flash EEPROM when writing large amounts of data. As of 2. 01. 3update,needs update flash memory costs much less than byte programmable EEPROM and had become the dominant memory type wherever a system required a significant amount of non volatile solid state storage. HistoryeditFlash memory both NOR and NAND types was invented by Fujio Masuoka while working for Toshiba circa 1. According to Toshiba, the name flash was suggested by Masuokas colleague, Shji Ariizumi, because the erasure process of the memory contents reminded him of the flash of a camera. Masuoka and colleagues presented the invention at the IEEE 1. International Electron Devices Meeting IEDM held in San Francisco. Intel Corporation saw the massive potential of the invention and introduced the first commercial NOR type flash chip in 1. NOR based flash has long erase and write times, but provides full address and data buses, allowing random access to any memory location. This makes it a suitable replacement for older read only memory ROM chips, which are used to store program code that rarely needs to be updated, such as a computers BIOS or the firmware of set top boxes. Its endurance may be from as little as 1. Grand Theft Auto Vice City Patch V3.1 on this page. NOR based flash was the basis of early flash based removable media Compact. Flash was originally based on it, though later cards moved to less expensive NAND flash. NAND flash has reduced erase and write times, and requires less chip area per cell, thus allowing greater storage density and lower cost per bit than NOR flash it also has up to 1. NOR flash. However, the IO interface of NAND flash does not provide a random access external address bus. Rather, data must be read on a block wise basis, with typical block sizes of hundreds to thousands of bits. Flash memory is an electronic solidstate nonvolatile computer storage medium that can be electrically erased and reprogrammed. Toshiba developed flash memory from. Find great deals for Apple MacBook Pro A1278 13. Laptop MD101LLA June, 2012. Shop with confidence on eBayThis makes NAND flash unsuitable as a drop in replacement for program ROM, since most microprocessors and microcontrollers require byte level random access. In this regard, NAND flash is similar to other secondary data storage devices, such as hard disks and optical media, and is thus highly suitable for use in mass storage devices, such as memory cards. The first NAND based removable media format was Smart. Media in 1. 99. 5, and many others have followed, including A new generation of memory card formats, including RS MMC, mini. SD and micro. SD, feature extremely small form factors. Apple serial number lookup tool. Find all the specs on your Mac with our serial number checker. Technical specifications for the MacBook Pro Core i7 2. Late 2013. Dates sold, processor type, memory info, hard drive details, price and more. Micro Center Web Store You are currently browsing the products available on our web store. If you would like to choose a store location, please do so below. How-to-Check-MacBook-and-iMac-Version-and-Specifications.jpg' alt='Flash Serial Number Macbook Pro' title='Flash Serial Number Macbook Pro' />For example, the micro. SD card has an area of just over 1. As of August 2. 01. SD cards with capacity up to 4. GB are available. Principles of operationeditFlash memory stores information in an array of memory cells made from floating gate transistors. In single level cell SLC devices, each cell stores only one bit of information. Multi level cell MLC devices, including triple level cell TLC devices, can store more than one bit per cell. The floating gate may be conductive typically polysilicon in most kinds of flash memory or non conductive as in SONOS flash memory. Floating gate transistoreditIn flash memory, each memory cell resembles a standard MOSFET, except that 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, electrons placed on it are trapped until they are removed by another application of electric field e. Applied voltage or UV as in EPROM. Counter intuitively, placing electrons on the FG sets the transistor to the logical 0 state. Once the FG is charged, the electrons in it screen partially cancel the electric field from the CG, thus, increasing the threshold voltage VT1 of the cell. This means that now a higher voltageVT2 must be applied to the CG to make the channel conductive. In order to read a value from the transistor, an intermediate voltage between the threshold voltages VT1 VT2 is applied to the CG. If the channel conducts at this intermediate voltage, the FG must be uncharged if it was charged, we would not get conduction because the intermediate voltage is less than VT2, and hence, a logical 1 is stored in the gate. If the channel does not conduct at the intermediate voltage, it indicates that the FG is charged, and hence, a logical 0 is stored in the gate. The presence of a logical 0 or 1 is sensed by determining whether there is current flowing through the transistor when the intermediate voltage is asserted on the CG. In a multi level cell device, which stores more than one bit per cell, the amount of current flow is sensed rather than simply its presence or absence, in order to determine more precisely the level of charge on the FG. Internal charge pumpseditDespite the need for high programming and erasing voltages, virtually all flash chips today require only a single supply voltage, and produce the high voltages using on chip charge pumps. Over half the energy used by a 1. V NAND flash chip is lost in the charge pump itself. RAM SSD Upgrades Apple Mac. Book Pro 1. 3 inch and 1. Mid 2. 01. 2sortprice high to lowprice low to high. Attributes. Attributes. Attributes. Attributes. Attributes. 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