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Guide To Flash Memory

As the digital world advances, so does the desire to retain the information that is gathered. That is no exception for products such as digital cameras, cell phones and MP3 players that appear to get smaller in size and greater in file saving capacity. We all want more music, pictures, contact lists, etc. to take on the road wherever we go in a device as small and lightweight as possible.

A huge element that facilitates the need to save media files are flash memory cards. Some devices come with a preset storage capacity while others can extend their amount of storage with the inclusion of a flash memory card. Currently there are over a dozen flash media cards available with some new ones ready to debut in the near future.

Such is the impact that many PCs and notebooks are including media readers in their systems to provide a simple method of extracting and writing files to the cards. Now, which card to utilize is dependent on the device you own or are looking to buy, where it is recommended to check the device manufacturer's documentation or web site for reference and compatibility. Below is a brief assessment of the current types of flash media cards in the market.

What Is Flash Memory

A memory card or flash memory card is a solid-state electronic flash memory data storage device used with digital cameras, handheld and Mobile computers, telephones, music players, video game consoles, and other electronics. They offer high re-record-ability, power-free storage, small form factor, and rugged environmental specifications. There are also non-solid-state memory cards that do not use flash memory, and there are different types of flash memory.

There are many different types of memory cards and jobs they are used for. Some common places memory cards are used include:

• in digital cameras
• in game consoles
• in cell phones
• in industrial applications.

PC card (PCMCIA) were among first commercial memory card formats (type I cards) to come out in the 1990s, but are now only mainly used in industrial applications and for I/O jobs (using types I/II/III), as a connection standard for devices (such as a modem). Also in 1990s, a number of memory card formats smaller than PC Card came out, including CompactFlash, SmartMedia, and Miniature Card. In other areas, tiny embedded memory cards (SID) were used in cell phones, game consoles started using proprietary memory card formats, and devices like PDAs and digital music players started using removable memory cards.

From the late 1990s into the early 2000s a host of new formats appeared, including SD/MMC, Memory Stick, xD-Picture Card, and a number of variants and smaller cards. The desire for ultra-small cards for cell-phones, PDAs, and compact digital cameras drove a trend toward smaller cards that left the previous generation of "compact" cards looking big. In digital cameras SmartMedia and CompactFlash had been very successful, in 2001 SM alone captured 50% of the digital camera market and CF had a strangle hold on professional digital cameras. By 2005 however, SD/MMC had nearly taken over SmartMedia's spot, though not to the same level and with stiff competition coming from Memory Stick variants, xD, as well as CompactFlash. In industrial fields, even the venerable PC card (PCMCIA) memory cards still manage to maintain a niche, while in cell-phones and PDAs, the memory card market is highly fragmented.

Nowadays, most new PCs have built-in slots for a variety of memory cards; Memory Stick, CompactFlash, SD, etc. Some digital gadgets support more than one memory card to ensure compatibility.

Types Of Flash Memory

A Brief Description Of Memory Devices
	SD HC is the new generation for SD cards larger than 2GB that adhere to the SD 2.00 specification - a new design that is required for cards and devices to support the SD HC 4GB to 32GB capacities.  CAUTION:  Check your device carefully before buying SD Memory.  SD HC will not work in SD 1.0 devices.  Use SD HC only in designated SD HC compatible products.  Consult your device's user manual or manufacturer's web site before purchasing an SDHC card for your device.
	Secure Digital Card (SD) Initially created to hold and prevent duplication of copyright music files, these cards have grown immensely popular with photographers due to their low power consumption and small size. There are now a few types of SD cards, offering transfer rates of varying degrees, that are slowly pushing CompactFlash cards (too bulky for many new cameras on the market) out of the camera accessory business.
	MiniSD Card Essentially identical in function to its big brother, the only difference of the miniSD is that it is almost half the size and used with cell phones, MP3 players and digital cameras requiring a much smaller card. An adapter is available for use with devices requiring a standard size SD card.
	MultiMediaCard (MMC) These cards are identical to the SD cards on the outside but work differently on the inside. They were interchangeable in some devices but not most and the SD tends to be favored for its fast speed in comparison to the lagging MMC.
	CompactFlash I (CFI) About the size of a matchbook, CompactFlash cards were one of the first to become standard in the digital camera market, ranging from 8MB to 8GB capacity. Containing both memory chips and a controller, these cards have made quite an impact to become a popular digital mass-storage device.
	CompactFlash II (CFII) CFII cards are identical to CFI with some minor differences. For one, CF II Cards are 1.7mm thicker than its counterpart and, secondly, those devices that contain CFII slots are backwards compatible with CFI Cards (doesn't work vice-versa). As with above, these cards are sold in capacity of up to 1GB (2GB and above only work with devices that utilize the FAT-32 file system)
	Smart Media (SM) This memory only card (no controller onboard but required on the device to be used) is used with digital devices pre-2001 and max out at 128MB. Not being so convenient to the advancement of technology, these cards are still available but taking a back seat to all the others out there, especially the xD-Picture cards (see below).
	XD-Picture Card (xD) The "new kid on the block" was developed jointly by Olympus and Fuji to replace the close to extinct SM Cards (previously favored by both companies). About the size of a postage stamp, this tiny giant can hold upto 8GB of data, knocking the wimpy 128MB max SM card out of the ballpark. As this card is fairly new, adapters are available to assist in using with your device/computer.
	Memory Stick (MS) Sony developed the Memory Stick in 1999 to create brand loyalty for their digital cameras and camcorders. Sometimes they are included with the camera or device in question. Most Sony notebooks do include a Memory Stick reader so users can remain within the spectrum of the brand and know their products will work with each other without fail.
	Memory Stick PRO (MS PRO) The PRO card was developed to provide even more capacity than MS (upto 4GB in comparison to the 128MB MS) and greater transfer speed. Most devices pre-2003 will not be compatible as will be certain card readers, with no adapter in sight.
	Memory Stick DUO (MS DUO) The DUO is exactly the same as the MS only half the size. Sony developed some products to utilize the compact card but an adapter is required for media readers to access the data.
	Memory Stick PRO DUO (MS PRO DUO) The PRO DUO is essentially the combination of the above four cards, being a perfect combination of compact size, high speed transfer rates and great capacity.
	TransFlash Card The exceptionally small size of TransFlash cards (11mm x 15mm x1mm) allows mobile phone manufacturers to incorporate significant amounts of removable storage capacity into their smaller handsets without changing the physical size of the phone. TransFlash is designed to store personal content such as digital images, MP3 music files, video games and other applications, phone settings and personal data.

Form Factors & More Specs

* Digital Rights Management Implementation

Since many EEPROM devices only allow a finite number of write cycles, some of these cards incorporate wear levelling algorithms to spread the wear and to avoid wearing out specific places which are often written to.

Console Game System Memory

Many video game consoles have historically used proprietary solid-state memory cards to store data, especially since games started being distributed in read-only optical discs. However, in the case of Sony game systems, industry standard memory was used for improve compatibility and availability of memory devices.

The sizes in parenthesis are those of the official cards.

• Microsoft Xbox console line:
  • Xbox Memory Unit (8MB)
  • Xbox 360 Memory Unit (64MB, 256MB, and 512MB versions)
• Nintendo console line:
  • Nintendo 64 Controller Pak (256 KB, divided in 123 pages)
  • Nintendo GameCube Memory Card (59-block (4 Mib/512 KiB), 251-block (16 Mib/2 MiB) and 1019-block (64 Mib/8 MiB) versions) This memory is simply a modified SD card.
  • Wii Memory Card compatible (see Nintendo GameCube  above) and SD Secure Digital card compatible
• Sega Dreamcast Visual Memory Unit (VMU) (128 KB divided in 200 blocks)
• Sega Saturn memory unit can hold 20 blocks of save games.
• Sony PlayStation console line:
  • PlayStation Memory Card (1 Mb/128 KB divided in 15 blocks)
  • The PocketStation can act as PlayStation Memory Card
  • PlayStation 2 Memory Card (called the "Memory Card (8MB)(For PlayStation(r) 2(r))" onscreen)
  • The PSP PlayStation Portable uses Memory Stick Duo.
  • The PlayStation 3 is compatible with CompactFlash, Secure Digital, and Memory Stick PRO.
• GP2X GNU/Linux based portable games console, uses SD/MMC.

Memory Cautions

It is vitally important to know what memory devices your product or system uses.  Two devices may look similar, but be totally different.  So compatibility is critical.  Always check your product's manual or manufacturer's website for memory compatibility.

Flash memory is not a hard drive.  It has a shorter life span, based upon the actual technology used.  Therefore, you should not plan to use flash memory as permanent storage, but as a floppy replacement - for temporary storage and transport.  For long term storage, transfer your data to a CD or DVD.

Do airport X-Ray machines damage Memory Cards?  Airport X-Ray Machines produce small amounts of static electricity.  Normally, the amount produced is safe for electronic devices.  However, many manufacturers suggest treating the cards as if they would be damaged by the x-ray machines. Also, DO NOT use the card as a means of long term storage of important files or photos. A small bolt of electrostatic charge will render the card useless and permanently destroy the files.

Glossary

• EEPROM (also written E²PROM and pronounced e-e-prom or simply e-squared), which stands for Electrically Erasable Programmable Read-Only Memory, is a type of non-volatile memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed.  EEPROMs are the memory technology used in most flash memory cards.