Definition of 'flash memory' from TechWeb :
A memory chip that holds its content without power.
Derived from the EEPROM chip technology, which
can be erased in place, flash memory is less expensive
and more dense. Unlike DRAM and SRAM memory
chips, in which a single byte can be written, flash
memory must be erased and written in fixed blocks,
typically ranging from 512 bytes up to 256KB. The
term was coined by Toshiba for its ability to be erased
"in a flash.
Flash chips have been used in various communications
and industrial products as well as to replace ROM
BIOS chips so that the BIOS could be updated. Flash
chips generally have lifespans from 100K to 300K
write cycles.
Flash memory chips are conveniently packaged as
"flash cards," using the PCMCIA PC Card format.
They are becoming more visible as solid state disks in
palmtops, digital cameras and, increasingly, in
consumer products.
There are two types of flash disks. The earlier linear
flash, which is also used to execute a program directly
from the chip (XIP), requires Flash Translation Layer
(FTL) or Flash File System (FFS) software to make it
look like a disk drive. There are various
implementations of FTL and FFS.
The second newer type is the ATA flash disk, which
uses the same 512-byte block size as a hard disk.
Since the ATA interface is a common standard, all
ATA flash disks are interchangeable. See
CompactFlash.
The CD-ROM version
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An 85MB Flash Disk
Flash disks are used in portable devices such as digital
cameras, palmtops and PDAs. They are considerably
more expensive than hard disks, but are much more
rugged and are not volatile. (Photo courtesy of
SanDisk Corporation.)
techweb.com
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