Years ago, I remember seeing my first CompactFlash card and thinking "Wow, that's tiny!". Before that, the only flash-based memory I had seen was in the form of PCMCIA cards, and those were very rare (didn't some early digital cameras take them?). Going from PCMCIA-sized cards to CompactFlash-sized cards was a huge leap, and when Secure Digital (SD) cards came out the change was just as radical - how much smaller could they possibly get? SD cards were the smallest form of flash memory I had ever seen, and they stayed the smallest for several years until two new types of memory came to market: miniSD and Transflash (I've never had a device that has used XD, so I'll just ignore that ;-)).
miniSD and Transflash: The Next Generation of Flash
If you've never heard of miniSD or Transflash, that's not surprising - the technology isn't very old, and there aren't many devices that use them yet. Sandisk sent me a 256 MB miniSD card for use on my Orange C500 Smartphone (awesome phone!) and they also sent me a 128 MB Transflash card. As the photo below shows, as small as miniSD is, Transflash is shockingly smaller. 8O
To give you a sense of scale, the 128 MB Transflash card was roughly the size of the nail on my pinky finger. That's small! 8O Why do we need smaller cards? Although I'm not a big fan of new memory types (interoperability is very important to me), as mobile devices become smaller, the need for smaller memory card formats becomes more pressing. Remember that there's an assembly inside the device that reads the card, so if new memory cards can be developed that have smaller read/write assemblies
and the cards themselves are smaller, significant space savings can be made. And as long as you can get an adaptor that will work in a slot that you have on your other devices, moving data around is fairly simple.
Why Go This Direction?
I believe that the driving factor is reducing the cost of the phones and increasing profit. Think about this scenario: the customer buys a new feature phone (camera/MP3 player) but the phone has a very small amount of built-in storage, say 8 MB - enough for quite a few pictures, but only one or two songs. When the customer buys the phone, they also buy a memory card that goes into the phone and stays there. If the way the phone works with the memory is completely seamless, this is a great solution.
By having a very basic phone with almost no memory, the cost to the carrier is greatly reduced, and the cost to the customer is also reduced (though we all know the carriers will pocket most of the profit there). Still, it means that they could sell an "MP3 Phone" at a very low cost - and allow the customer to customize how much memory they want. 64 MB? 256 MB? 1 GB? Get whatever you want, put it in the phone, and forget about it.
Why Put Cards Under Batteries?
A common complaint about some new mobile devices (usually phones) is that the memory cards are not easily accessible: they usually go under the battery, making the process of removing/swapping out the card awkward. Why do the manufacturers do this? It depends on the intent of the device. In the case of my Orange C500 phone, the miniSD slot is under the battery, but that doesn't bother me at all. Why? Because I never take it out - it's like RAM in my desktop computer, once I put it in there I forget about it.
Other decisions, like Nokia putting the memory card under the battery then selling "game cartridges" that encourage the user to swap out the card on a regular basis, make no sense. The only time a memory card slot should be hidden under something else is if it's meant to be accessed very infrequently - as in, once or twice in the life of the device.
What's Next?
In larger devices such as PDAs, I think in the future we'll see more dual-slot devices: a miniSD or even Transflash slot under the battery for a one-time (but upgradeable) expansion of storage memory, and an external SD card slot for swapping memory cards with digital cameras, MP3 players, etc. This would give us the best of both worlds, especially if the operating system on the device could look at that memory as being the same. Now wouldn't that be nice?
UPDATE: Smartphone Thoughts reader
Bushrod asked about transfer speeds to the phone, which is something I hadn't thought much about (with only 256 MB, I haven't put much music on the card). So I did a test: with the C500 connected to a USB 2.0 port, I copied over a 4 MB WMA file and it took 15 seconds. By way of comparison, with the same miniSD card in an SD adaptor and connected to a USB 2.0 external memory card reader, the same 4 MB song was copied over in 2 seconds. 8O So that's definitely a weakness in this scenario - if the customer has a 1 GB miniSD card and regularly refreshes it with new music, they could be in for a long wait. Clearly, we need to see greater speeds from our mobile devices.
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