Flash memory refers to a particular type of electronically erasable programmable read-only memory (EEPROM). It is a computer memory chip that maintains stored information without requiring a power source. It is often used in portable electronics, such as digital music devices, smartphones and digital cameras, as well as in removable storage devices. This technology also is useful for computer basic input/output systems (BIOS), Personal Computer Memory Card International Association (PCMCIA) cards, modems and video game cards.
Flash memory differs from regular EEPROM in that EEPROM erases its content one byte at a time. This makes it slow to update. Flash memory can erase its data in entire blocks, making it a preferable technology for applications that require frequent updating of large amounts of data, as in the case of a memory stick for a digital electronic device.
Inside the flash chip, information is stored in cells. A floating-gate transistor protects the data that is written in each cell. Tunneling electrons pass through a low conductive material to change the electronic charge of the gate "in a flash," clearing the cell of its contents so that it can be rewritten. This is how flash memory gets its name.
Nonvolatile and Silent
Flash memory used as a hard drive to store data on a computer has many advantages over a traditional hard drive. It is nonvolatile and in a solid state, which means that there are no moving parts. It also is silent, much smaller than a traditional hard drive and highly portable, with a much faster access time. A traditional hard drive has the advantage over a flash drive in price and capacity. Hard drives are many times larger for a price that is cheaper per megabyte of memory.
Advances in Technology
The price of flash memory has continued to drop, and its capacity has continued to rise. This makes it a prime candidate for an ever-broadening set of applications. It is especially popular in portable electronics. A memory stick can store pictures in a digital camera, for example, then be removed and inserted into a computer, where the pictures can be accessed.
Flash memory is not the same as flash random access memory (RAM). Flash RAM, like any type of RAM in a computer, requires a continual power source to maintain its contents. When the power is lost or turned off, the flash RAM is wiped away. Flash memory, on the other hand, will remain on the chip or memory stick even when it is not connected to a power source.