Micro SDHC Cards

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Originally Posted By: PandaBear

Originally Posted By: JHZR2
im not using it in a phone, rather like a usb drive with swappable memory innards.


I'd use a faster interface memory like USB stick than a USB adapter with MicroSD. The bottleneck would still be in the SD interface and since you have much more room with USB, you can just use a native USB interface stick.


Ive lost too many USB flash drives due to corruption to feel that they are trustworthy. As I understand it, the issue is usually not with the chips, but rather with the controllers in the USB drives.

So my thought is that if I use a micro SD, I get a really tiny drive to hold stuff in, and if the controller fails, I just move the memory chip over to another interface.

Is that not sound logic?
 
My experience is that if you want fast, you have to move away for Micro SDHC and settle for standard SDHC or USB stick. I still like Micro SDHC because of the form factor and in a pinch can be used anywhere with the right adapter. I have the reader dangling from my keychain and adapter somewhere in the house.

- Vikas
 
Originally Posted By: JHZR2
Ive lost too many USB flash drives due to corruption to feel that they are trustworthy. As I understand it, the issue is usually not with the chips, but rather with the controllers in the USB drives.

So my thought is that if I use a micro SD, I get a really tiny drive to hold stuff in, and if the controller fails, I just move the memory chip over to another interface.

Is that not sound logic?


Micro SD is still a card with memory and controller inside, except they are packed on top of each other with very high density. IMO the probability of failure will be identical if you buy the same brand of Micro SD vs USB. At least one brand I know share all of the design of hardware and software of controller between different types of card except the interface. There used to be a very cool card from SanDisk called SD plus, you can fold an SD card over and it will becomes a USB:

41VE9WGKEKL._SL500_AA300_.jpg


IMO, a lot of the failures are on the computers and cameras side that end up being on the card side. I've once help my friend recover a CF card and realized the card is actually fine according to all the internal structure, but the camera crashed in a loop trying to write the same photos 500+ times.
 
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Excellent thread here, & the link to the card thread on XDA was pure gold. PandaBear & others: Thanks for sharing your knowledge & experience! This has saved me from buying a Class 6 or 10 card for my new Nook Color, which would probably have made rooting it a disaster. It's gonna get a Sandisk Class 2 or 4 instead, probably a 16GB.
 
Panda, thanks for the clarification. If the good Sandisk cards are hard to come by, it's no sense in using this as a tablet any longer.

Stuart, you know anyone else that wants to buy a Nook Color, with a 2 year warranty? I'm tired of fighting the good fight with this thing. I have 5 different cards, all suck. The internal hack, which is easy, is buggy at heck after the NC 1.3 upgrade. Too much time spent trying to make this a cheap tablet.

As a book reader, it's great, especially when Road & Track only costs $0.99 per month! But I just don't read enough to warrant keeping this unit.
 
I don't know anyone looking for one, but I bet you could find a buyer easy on the Androidtablets dot net or the XDA forums, in the Nook Color section.

Do you have a Sandisk 8 or 16GB microSDHC Class 2 or 4? If so, & the NC acts draggy wth it, have you tested the card with the CrystalDisk program? I know *Nothing* about rooting/etc except what I've read since getting interested in the NC, but that long thread at XDA forum has many posts from folks who found their NC so sluggish &/or balky as to be worthless & then all went well after loading the programs onto a Sandisk Class 2 or 4.

I'm probably going to order this Sandisk 16GB Class 4 for my NC: http://www.amazon.com/Sandisk-16GB-MicroSDHC-Memory-Class/dp/B001F7AJKI/ref=cm_cr_pr_pb_t

I downloaded the CrystalDisk program last night & tested my only microSD card, a Kingston 8GB Class 4- very slow on 4KB write speeds, 0.019 MB/s in 4K QD32, even slower in the plain 4K test at 0.006 MB/s.
shocked.gif
 
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Originally Posted By: Stuart Hughes

Do you have a Sandisk 8 or 16GB microSDHC Class 2 or 4?


Almost all card 4GB and above will be SDHC due to the limitation of the interface (byte vs sector addressable) and SDHC has a minimum spec of class 4, so 8-16GB Class 2 is impossible to find.

You might be able to find an old card with class 4, maybe used, but newer inventory are unlikely. Like I said, older memory are bigger in silicon die size (surface area), so it is more expensive to make, but faster (need less precise of a voltage control). This is the opposite of hard drive or CPU.
 
Originally Posted By: PandaBear


Micro SD is still a card with memory and controller inside, except they are packed on top of each other with very high density. IMO the probability of failure will be identical if you buy the same brand of Micro SD vs USB. At least one brand I know share all of the design of hardware and software of controller between different types of card except the interface. There used to be a very cool card from SanDisk called SD plus, you can fold an SD card over and it will becomes a USB:

41VE9WGKEKL._SL500_AA300_.jpg


IMO, a lot of the failures are on the computers and cameras side that end up being on the card side. I've once help my friend recover a CF card and realized the card is actually fine according to all the internal structure, but the camera crashed in a loop trying to write the same photos 500+ times.


So then are you saying that the most common failure modes are due to the end user's software, rather than the stick?

Ive lost two, a sandisk cruzer mini and a kingston. Both are fairly low capacity, compact, run of the mill USB drives. I always stop them before pulling them, and always make sure that all the lights are not flashing. I dont think Ive done anything abusive to them, they arent nearly full, and they just loose data or wont mount properly.

What is that an indicator of? What are the common failure modes/data loss modes on flash memory (USB sticks and SD cards)?

Thanks!
 
You must go through alot of memory cards. Never had a memory chip go bad in any size including usb. Not alot to go bad so I thought. Even had 2 go through the washer. Bought a Sansdisk 8gb mirco for the Samsung Reclaim just for music no issues yet.
 
Originally Posted By: Eric Smith
You must go through alot of memory cards. Never had a memory chip go bad in any size including usb. Not alot to go bad so I thought. Even had 2 go through the washer. Bought a Sansdisk 8gb mirco for the Samsung Reclaim just for music no issues yet.


Well I dont go through flash memory, use USB sticks. I dont keep them in my pocket or harsh place either, its just that they fail to mount or loose data after a year or two of use.

My CF and SD cards that I use in my cameras dont ever fail, though they get written with a lot more data (maybe not overwritten as often).
 
Originally Posted By: JHZR2

So then are you saying that the most common failure modes are due to the end user's software, rather than the stick?

Ive lost two, a sandisk cruzer mini and a kingston. Both are fairly low capacity, compact, run of the mill USB drives. I always stop them before pulling them, and always make sure that all the lights are not flashing. I dont think Ive done anything abusive to them, they arent nearly full, and they just loose data or wont mount properly.

What is that an indicator of? What are the common failure modes/data loss modes on flash memory (USB sticks and SD cards)?

Thanks!


From my understanding it is not due to the wear and tear of the memory chip's cell inside the cards, as in, you are not writing them too much.

Most of the ones I've seen (may not be statistically accurate) has to do with the power off behavior or voltage stability of the computer. When you write something on a card there are a lot of stuff being shuffled around in the middle of the process depending on the design. Some of them are shuffling blocks around for wear leveling, some are shuffling pages around for garbage collection to free up new spaces, some has to do with the file location changes (file system issue). If the design does not have redundancy to tolerate power off at any point no matter how small, there will be a window of time that the card will be stuck in limbo and never boot up again (internally). The file system is protected if you use a journaling file system like NTFS, but inside the card really depends on the firmware design. Usually the major brands and those with professional series cards have better design than the no name brand who use whatever cheapest controller they can find in the spot market, and newer cards have better stability than older cards (in general) to handle this.

Unfortunately you won't see any indicator without factory tool, and the best you can do is backup your data frequently and warranty any questionable cards.

You'd be surprise how a lot of cards' internal firmware crashes because of bad power supply that causes voltage dip or spike for short period of time. That's why Memory Stick tends to be more reliable because it is only used on Sony and their electrical spec tends to be better than the no name brands.

Most of the time, the card isn't really electrically dead, just the internal layout corrupted.
 
Usually in terms of industrial practice, I "think" the part number using 8192 instead of 8 to indicate 8GB of space will be older design, as well as the earlier suffix like A11M instead of B35A. I no longer have inside information and even if I do I cannot give you, so my speculation would end here.

However, the "style" of the microSD to SD adapter style history of "red top, blue bottom" is older as well as the "wake up your phone" campaign vs the red and white only style they use now.

So all indicates that this is an older design that may be better for you need (no guarantee however):

http://www.newegg.com/Product/Product.aspx?Item=N82E16820171363
 
PB,

Bought those cards, Android 2.3 CM7 (2.3.7 in this case) runs A-OK from them after a month of use. A WORLD of difference from the class 6 or class 10 cards. The CM7 sdcard-only process is quite easy compared to rooting the unit directly which brings a host of other issues along with it.

It's sill not as zippy as built-in 8GB or 16GB of flash storage. But hey, free Android tablet, without Carrier IQ!
smile.gif


Honeycomb 3.0b4 works OK on these cards but trying to get the Google app market on it is a painful process. Gingerbread, 2.3, works fine for the intended purpose.

What is astounding to me is the battery life while streaming talk radio, only 15% used for about 4 hours. My iPhone would be dead by then. The key is to keep the screen off (oh the irony) as it drains the battery more than anything else.

And now the Nook Color Tablet has arrived. Non B&N apps can be installed with a simple 'hack'. And you get an SD card slot to hold all your music, vids and pics. People are enjoying using the Google & Amazon (oh another irony) app markets on a stock B&N Nook Color Tablet w/o any rooting.

Thank you for the ultra-insightful info PandaBear!
 
Nice to know that it works. There is NOTHING that will work as fast as internal NAND inside the device with the OS managing the file system itself. You will need something like a Compact Flash or USB to match the speed of one NAND chip, so a MicroSD interface will definitely be the bottleneck of your system.

Regarding to the battery life. These tablets have much more battery capacity than phone. Even with 3G capability, a phone has to "listen" for incoming call all the time while the data only device only has to connect when it feels like, that's a measurable difference in terms of power consumption.
 
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