Digital cameras are designed to capture images via an electronic image sensor. It utilizes a form of removable storage called flash memory, one of the essential digital camera accessories. Flash memory is a non-volatile (no-power consumption) EEPROM (Electrically Erasable Programmable Read-Only Memory) type that can be re-used and re-programmed. It offers fast access time for reading information and images.

The first flash memory was invented by Dr. Fujio Masuoka in 1980 at Toshiba circa. The name flash was advised by Mr. Shoji Ariizumi (Dr. Masuoka's colleague), reminding him of the camera flash.

A flash memory stores information in a number of memory cells, made from floating-gate transistors. It is made with a card case durable enough to withstand pressure, temperature and water. It can be inserted to a camera compartment. Images are taken and processed automatically. It has a range capacity of 128 megabytes to a number of gigabytes. More pictures can be stored in a high storage capacity memory.

Below are a few examples of flash memories:

CompactFlash

CompactFlash is a 50-pin digital camera memory card. It is used in many applications used to interface with PCs, PDAs and printers. Type I and Type II are the 2 physical sizes available. Some cameras accept only Type I. Type II is much thicker and has a higher capacity. One common Type TT cards is the MicroDrive memory card. It also has a built-in controller chip. This allows higher transfer rates on cameras with larger internal buffers.

CompactFlash was built something similar to Intel's NOR-based flash memory. It became the oldest and most inexpensive formats in the market today. It is available in 512 MB (megabytes) to 100 GB (gigabytes) capacity. 1 GB and 16 GB are one of the popular choices in North America and Europe.

CF memory cards are the most desirable types because of its rugged design. It withstands more physical damage as compared to other portable storage devices. It lacks the write protection switch that other devices have in common.

Secure Digital (SD)

Secure Digital is one of the non-volatile memory card format widely used in digital cameras, computers and mobile phones. The slim and compact design is just about the size of a postage stamp. A decoder software of SD enables you to play music and video clips.

SD was developed by Matsushita, Toshiba and Scandisk. The card ranges from 4 MB to 4 GB. It has a physical size of 24 mm × 32 mm × 2.1 mm, providing both DRM to a SDMI standard.

SD cards are supported by the older MultiMediaCard (MMC). It has a transfer rate of 10-20 Mbytes. It supports at least three of the transfer modes. These include the One-bit SD mode (separate data channels, commands and transfer format), Four-bit SD mode (uses reassigned and extra pins) and the SPI mode (subset of the SD protocol use with microcontrollers).

Memory Stick

A memory stick is a kind of digital data storage launched by Sony last October 1998. It is designed for small digital products because of its compact design. The 8 MB memory stick is available in 4, 8, 16, 32, 64 and 128 MB storage sizes.

This type has a data transfer rate of maximum 20 MHz with a 10-pin connector type. An Erasure Prevention Switch can set lock to eliminate accidental erasing or recording of data. It also has original serial protocols for compatibility issues. It includes a family of Memory Stick PRO, Memory Stick Duo, Memory Stick Micro (M2) and the Memory Stick PRO-HG.