James,

On Mon, 6 Nov 2006 11:30:39 -0800, James Newton, Host wrote:

> I've been doing some work for a guy who makes data loggers and we are
> looking at a new memory card for the loggers. I found these microSD cards
> and I have to say I'm really impressed:
> 
> - 512MB for $18, 1GB for $30. 2GB for $90. Cost is low because they have
> been made in extreme volumes.
> - Unlikely to go away since they are used in most cell phones as the "sim"
> card or more: the new Chocolate phone uses a 2GB version for internal music
> storage.

That's not quite right - SIM cards use the "Smartcard" format, a piece of credit-card-like plastic card with the gold contact pads arranged in two 
rows around a central long connection, like this:  http://www.brightmobile.com/images/sim%20virgin.jpg  (it's made in a credit-card size, then the part 
around the chip/contact is broken out to insert into the phone).  SD and its smaller brothers are used for storage of other things - my current phone 
has a SIM as I described, and an SD slot that it used as a "disk", for storing software, music, photos, video, and basically any data files you want.  The 
only data on the SIM is the phone/account identity information and a small "contacts" list - probably no more than about 32kB, and maybe much less.  
The SD card can be 1GB or more.

> - About the size of your thumbnail.
> - Plugs into a standard SD slot with a mechanical adapter.
> - Same SPI serial or nibble parallel interface as SD cards.
> - Easy USB interface via "expandable" memory sticks.
> - High reliability connectors that hold the entire card down at reasonable
> prices.
> 
> Just seems ideal for large memory applications in the embedded world.

It's been said (and I can't remember where I saw it) that microSD cards aren't designed for regular insertion/removal the way SD, Compact Flash and 
so on are, because of their size and other aspects, but are really intended to be inserted (into the phone, MP3 player, or whatever) and left there 
most of the time.  With my phone I often take the SD card out to transfer stuff to and from a PC (easier than finding the cable! :-) but with microSD 
that's a Bad Thing!  If you don't need that tiny form-factor, it's probably best to go with full-size SD.  (Good grief, I'm saying "Full size" - we're 
talking about something you could hide under your watch! :-)

Cheers,


Howard Winter
St.Albans, England


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