microSD or microSDHC?
 

Next week I will be picking up my N900. I want to buy a microSD memorycard for it, but I'm confused.

In the (digital) manual from the N900 I read that I should use microSD cards (also on the Nokia N900 productpage). But when I visit the shop and look at the accesoires there is a microSDHC card listed: "Nokia 16 GB microSD-kaart (MU-44)".

I assume that only microSD's are supported?

Re: microSD or microSDHC?
 

HC stands for High Capacity

Re: microSD or microSDHC?
 

I know. But I'm not sure that microSDHC is backwards compatible with microSD.

Re: microSD or microSDHC?
 

It definitely supports microSDHC: I've just looked at the 8 gig card I regularly use witn my n900...

Re: microSD or microSDHC?
 

Yes, of course they're fully backwards compatible. It'd be rather silly if it wasn't.

Just like USB 2.0 is backwards compatible with USB 1, etc.

Re: microSD or microSDHC?
 

Thanks for the info TomJ, that leaves no room for argument.
Too bad this info isn't put in the manual or on the websites...


Except that devices NOT designed for microSDHC cards can't access those (as far as I know, please correct me if I'm wrong). Of course devices designed for microSDHC can access the "older" microSD.

Re: microSD or microSDHC?
 

That's correct. microSD had a maximum size of 2G (IIRC), and microSDHC has a maximum of 32G. You're unlikely to run across any modern equipment (except for, in my experience, all-in-one card readers) which don't support SDHC.

Re: microSD or microSDHC?
 

The 8 GB microSDHC card in my N900 that works fine.

A 16GB SDHD card works fine in my N800 after updating the firmware to Diablo even though the original firmware only supported SD cards up to 2GB.

This is largely a software issue caused by the older cards using a FAT16 filesystem to support up to 2GB. The newer HD cards use FAT32, and the XD cards will use yet another filesystem to go beyond 32GB.

Re: microSD or microSDHC?
 

Btw, is A-Data a good memory card manufacturer?

A-Data 8gb class 6 microsd card costs around 26 $ in ebay, and they advertise life-time warranty in A-Data's web site.

Re: microSD or microSDHC?
 

Well, I think my nest device will be one supporting SDXC. I have a camera supporting sdxc and I want to use a microSDXC in it and on my next smartphone.

Re: microSD or microSDHC?
 

microSD is 2 GB and below.
microSDHC is between 4 and 32 GB.
microSDXC is 64 GB and up.

Re: microSD or microSDHC?
 

So it means I can only go upto to 64GB for my N800 -- I am a bit disappointed :-) Would n900 be modified to support microSDXC?

Re: microSD or microSDHC?
 

I think it requires both hardware and software changes (as did microSD to microSDHC), so I doubt it. There a bit of a question over general Linux support for SDXC anyway, as the filesystem used is proprietary and patented. I guess Nokia could do a licensed closed-source implementation though.

Re: microSD or microSDHC?
 

Can't say for certain.. but its pretty unlikely.. it also is a fairly long way off. However, if we get USB Host working.. you can have up to 2TB with an external harddrive :P

Re: microSD or microSDHC?
 

I can vouch for A-Data's quality - except that I was using the full SDHC, not the micro version, so perhaps the plasticky look won't be present.

Re: microSD or microSDHC?
 

Re: microSD or microSDHC?
 

Thanks for all the feedback, now I can order a microSDHC card knowing my N900 can use it.

Re: microSD or microSDHC?
 

i have an a-data 4gb class 6 microsd and it is super fast... about 26MB/sec writes in my card reader. Been using it for a couple years and no problems. Hopefully they have maintained that level of quality.

I have a transcend 8gb microsd and it is garbage, everything becomes corrupt no matter what device I use it on. It is useless.

Also beware of no-name cards that claim to be high speed, they are usually lies...

Re: microSD or microSDHC?
 

I've got my eyes on a 4gb card from Dane-Elec. My experience with Dane-Elec is that they are not expensive and perform well.

Re: microSD or microSDHC?
 

i have a 2GB microSD, 8, 16 and 32GB microSDHC and everything is working fine on my n900

Re: microSD or microSDHC?
 

Basically, here's the situation:

• In terms of hardware, SDXC slots are exactly the same as SDHC slots.
• Linux (including Maemo) has supported the extra addressing bits needed for SD cards larger than 32GB since SDHC support was originally added to it.
• The FAT32 filesystem, as used by SD and SDHC cards, can't grok storage larger than 32GB, so SDXC uses a new Microsoft filesystem: exFAT. Windows Vista SP1 and above support it.
• Yes, Microsoft does demand royalties from everyone else who uses exFAT. Thanks for asking!
• A company named Tuxera has signed contracts with, and paid money to, Microsoft for exFAT and has developed exFAT support for embedded Linux systems. The driver isn't free by any meaning of the word.
• Android uses Tuxera's solution and was the first mobile OS with SDXC support.
• MeeGo uses Tuxera's solution. Really.
• SDXC cards reformatted with other, Linux-supported, non-exFAT filesystems will work fine in Linux, Maemo included. Technically, the cards are no longer SDXC cards though, and they won't work in devices or computers that don't support those alternative filesystems. So, 64GB of videos on an Ext3-formatted SDXC card popped out of your N800 will likely completely fail to be recognized in the SDXC slot of your Windows notebook/television/Blu-ray player/toaster.

Re: microSD or microSDHC?
 

My understanding of SDXC is that unlike the SD/SDHC hit, the current version of the SDXC cards (Using SD3.0 format) should work in SDHC readers if they can talk that format (may require a flash update). There is some doubt as to the capability of them to read the (as yet unimplemented) SD4.0 format though, even with firmware updates.

One thing to note is that technically the capacity for SD (SD1.0) was 512M, but using some tricks (changing sector sizes mainly) you can boost that up to 4G (using the SD1.01 format). The same trick can expand SDHC up to 2T, so SDHC is not necessarily capped at 32G. SDXC is capped at 2T, and the SD3.0 definitions show the most expansion using the current tricks would be 16T. The SD4.0 format for SDXC may expand it up that high, but that's the current limit for that format.

Re: microSD or microSDHC?
 

FAT32 can use partitions larger than 32G just fine. Even windows machine can read/write such partitions. There an artifical 32GB limit to formatting FAT32 partitions in Windows XP and later systems. Linux and Windows third party tools have no problem formatting largerthan 32GB partitions to FAT32.

Re: microSD or microSDHC?
 

Windows puts an arbitrary limitation on *creating* FAT32 partition greater then 32GB, for a simple reason. All sorts of simple operations start taking ridiculous amount of time, like calculating the amount of free space. If you take a ~1TB sized partition and run the windows dir command, you will see that it stays stuck on the last line for a bit to calculate the free space.