kanniya wrote:Just wanted to check if the B+ unit supports micro SD card ? Samsung Electronics 32GB EVO Micro SDHC Upto 48MB/s Class 10 Memory Card- Kanniya
It'll work with that or any other 32GByte card. The lower the class the lower the speed. That's actually a UHS1 card so it will probably be a lot faster than the 32GByte Sandisk (non-UHS1) card I have in my B+.
There are, however, a lot of caveats. These aren't RPi specific or, indeed, specific to the Samsung card.
1) Based on reading reviews on the US Amazon an increasing number of sellers are selling 32GByte and (particularly) 64GByte flash cards that are actually 4 or 8 Gbyte cards that have been reprogrammed to believe they are 8x bigger. The computer *inside* the card doesn't realize this until the user has actually written a full 4/8Gbyte of data to the card, at which point the card fails. Google "fake SD card". Well known brand names have the problem, it's the highwayman dilemma; if you are going to be hung for robbery at gunpoint you may as well take the chance of not being hung for murder. Well, it's also the Dude problem; Dudes ("Doods") have really big cards but nothing on them, so they never notice.
2) The hardware supports that card, but the operating system has to as well. How well the card works depends on how well the operating system supports it.
3) Linux doesn't support SD cards used as operating system file systems very well. There is support in current RPi Linux versions for Samsung's F2FS file system, it seems reasonable that the Samsung card will probably work very well with F2FS as a root partition (you can't change the boot partition, it has to be FAT32, but it's not written very much so it doesn't matter.) I run F2FS on my B+, it's ok.
4) Even with F2FS how long the card lasts will still be a function of how carefully you configure the operating system. Actually writing temporary data to the flash card is probably a mistake, unless you have to because you hit the limit of the B+ DRAM. Whether this matters depends on how much temporary data your application generates; I can't imagine it being a problem with a controller application but if the application is doing a lot of video that might be different.