Can someone explain the difference between Compact Flash, SD, and MMC

[biggiesmallz]

Which are compatable with which.

Also does the SD format give unnessecary problems with their copywrite protection scheme.

Also which is best.


Thanx in advance

 

[AndyHui]

Compact Flash is probably the most common, but one of the larger size formats. It is relatively robust, and you can have sizes up to about 1GB. Lots of digital cameras use CF.

SD and MMC are interchangeable; SD is the more advanced version of MMC and supports encryption. I haven't heard of any reports of problems with the SD encryption. SD/MMC are used in digital cameras (mostly Panasonic/LEICA) and a few other places like Palm Pilots and MP3 players. Capacities for SD are now at 1GB and 2GB in Japan. The physical size of SD/MMC is much smaller than CF.

The new XD is supposed to replace SD/MMC and is 1/3 of the size of SD/MMC. There are very few products that use XD at the moment though.

Best depends on personal preference and what sort of product you want to buy. I would generally buy CF or SD. I wouldn't bother with MMC. XD, as I said, is still difficult to purchase.

 

[Mday]

compact flash not really purely flash memory in nature. the specification makes it a mini pc card (laptop), that's why you see so many pins. that's also why you can find so many non-memory devices that implement the compact flash formfactor.

SD\MMC is the same family in terms of ownership. they are not inherently interchangeable. mmc support does not guarantee sd support. but sd support should necessarily guarantee mmc support.

both media have the memory controller built in, so expansion is not a problem. ie, you should be able to use a larger card no matter what. though, this has proven to be not true with cheap devices which do not implement the specification properly. this is a stark contrast to smart media and it's xD replacement. smart media and xD do not have the memory controller built in. so, basically, if the device does not support larger capacity cards, you're out of luck.

xD and sd are competing standards. i would consider them comparable in size. though xD is smaller. sd was supposed to replace compact flash. xD media is very plentiful in retail stores. the relation of media families are really about the companies backing them.

also, compact flash is huge. i would not get compact flash unless i had to. sure it's cheap, but that's not my only primary concern. I use a 256MB SD card on my dell axim (lexar, not sandisk). the compact flash slot is being used by a wifi adapter =D

 

[eklass]

it's like the difference between FAT, NTFS, and ext2... just different ways to accomplish the same thing
each has it's own benefits/pitfalls, and some argue that one in particular is much better than the rest

 

[biggiesmallz]

What about SmartMedia Card?

What's the situation with it? Compatability and such?

 

[Mem]

SmartMedia

Physically smaller than a book of matches and about as thick as a credit card. SmartMedia (SM) cards have no controller, they are simply memory that has been laminated on a plastic card. The controller has to be built into the camera and this causes incompatibilities with cameras made before 2001 and the new, higher capacity 64MB and 128MB size cards.

Before you buy a 64MB or 128MB card for your pre-2001 camera, check to see if your camera can accomodate it.



It's now 2003 and SmartMedia cards -still- top out at 128MB. Where are the bigger SM cards?   Nobody has come right out and said it but, SmartMedia memory is pretty much dead in the water at 128MB and we do -not- expect to see any further capacity increase.

Info on memory types can be found here at Steve`s Digicams .

 

[biggiesmallz]

Originally posted by: Mem

SmartMedia

Physically smaller than a book of matches and about as thick as a credit card. SmartMedia (SM) cards have no controller, they are simply memory that has been laminated on a plastic card. The controller has to be built into the camera and this causes incompatibilities with cameras made before 2001 and the new, higher capacity 64MB and 128MB size cards.

Before you buy a 64MB or 128MB card for your pre-2001 camera, check to see if your camera can accomodate it.



It's now 2003 and SmartMedia cards -still- top out at 128MB. Where are the bigger SM cards?   Nobody has come right out and said it but, SmartMedia memory is pretty much dead in the water at 128MB and we do -not- expect to see any further capacity increase.

Info on memory types can be found here at Steve`s Digicams .

Thanx to all who replied.