Electronic Flash Cards

Compact Flash (CF) is a type of data storage device, particularly useful for portable electronics. It can be used directly in a CF card slot with an adapter. It uses flash memory. On the basis of physical characteristics, there are two types of flashcards: Type I (3.3mm thick) and thicker Type II (CF2) cards (5 mm thick).

First produced in 1994 by SanDisk, Compact Flash is among the earliest and the oldest and most successful brands and is now used for a variety of devices including laptops, notebooks, audio recorders and desktop computers and cameras.

Flash memory devices consume very less power and have good transfer speeds. They can also pass from one system to another. They are also designed to adapt to rapid changes in temperature or voltage. The storage capacity of a Compact Flash card varies from 128MB to about 64 GB. However, 256 MB and 2 GB is the most popular choices in Europe.

Flash memory has a special quality that allows a section of its memory cells forever erased in one fell swoop, "recalls many a camera flash function. This reminds one of the ease with which data erasure can be carried out, freeing space for new data on it. Flash memory is nonvolatile state and solid, can be electrically erased and rewritten. Flash memory allows multiple memory locations must be erased or written in one programming operation. It can therefore operate at access speeds significantly higher in reading. Best shock resistance than hard disks is another of its useful features. Characteristics of these cards make these much more preferable over the other like devices powered by battery.

A limitation of this card is that memory is easily rewritable, it can be overwritten without warning resulting in loss of data. System failure, power fluctuations, corruption caused by accident or equipment malfunction software are other limitations.

Flash memory stores one bit of information in an array of transistors, called "cells". Compact Flash Cards are built based on the type of logic gate used in each bin and are of two types: NOR flash and NAND Flash. Recently, however, some flash memory devices called multi-level cell devices, can store more than one bit per cell. NOR flash memory cell has two doors: the control gate and the floating gate. NAND Flash has a different mechanism: tunnel injection for writing and tunnel release for erasing.
Market demand today is tilting toward the low-cost NAND flash.