Rapsberry PI 2 MicroSD

[w4mmp]

Hi,
What are the specs on the Microsd slot? UHS-I,UHS-II???

Thanks,
Ron

[fruitoftheloom]

Hi,
What are the specs on the Microsd slot? UHS-I,UHS-II???

Thanks,
Ron

It is a standard SDHC, suitable for Class 4, 6 or 10 Cards

http://en.wikipedia.org/wiki/Secure_Digital

[w4mmp]

Thanks very much. My microsd is a class 10 so the RPI is doing the best it can.

[fruitoftheloom]

Thanks very much. My microsd is a class 10 so the RPI is doing the best it can.

Actually Class 4 or 6 are more suited to the RPi I/O, many posts on this subject

[DougieLawson]

Thanks very much. My microsd is a class 10 so the RPI is doing the best it can.

Actually Class 4 or 6 are more suited to the RPi I/O, many posts on this subject

It largely depends whether you're running it in a normal configuration. Class 10 would be ideal for a RPi with a camera collecting big timelapse photos. For most users, most of the time the class of their SD card doesn't matter and they won't be able to tell (because most computers spend lots of time waiting for the warm body behind the keyboard to respond to prompts on the screen). If you have an application that has high volume and high speed collection of massive blobs of data use a USB hard drive.

[LitterBugs]

Thanks very much. My microsd is a class 10 so the RPI is doing the best it can.

Actually Class 4 or 6 are more suited to the RPi I/O, many posts on this subject

This mythical information about class 4 and 6 cards being better suited for the RPi is not based on fact and should stop being perpetuated without details to back it up. Sure there are a large number of posts stating it, but that does not make it a true statement. The "class" number of a card is the "minimum serial data writing speed" of the card and does not paint the whole picture of the performance of the card. (see https://www.sdcard.org/consumers/speed/ ) The benchmark used to set the speed class of a card is not an all encompassing test and only represents one aspect, "serial data writing". That is NOT the type of access that you will typically see when running an Operating system as is done on the Raspberry Pi. You need to take into account reads AND writes, of varying sizes, in random AND serial order to get a true picture of what the performance of the card is. Another myth I have seen perpetuated is that the 4K reads and writes are what really matters. That is only true if all you do is read and write 4k sized files. Again, that is NOT a fact.
In January, I bought my first two RPi B+ units used from a grad student who believed that "class 4/6 theory" which had been perpetuated by his professor and he tried to get me to buy into it as well. It took close to 10 minutes to boot with a fresh image of Raspian. So I started looking around here on the forums to see what a typical boot time should be and quickly realized that my "fast class 4" cards were extremely slow. I also kept seeing this "Myth" being perpetuated in a lot of messages when trying to find out what a better card would be for the RPi. Not finding much info based on fact and seeing info based on tests run mostly on windows rather than on the RPi, I started benchmarking cards myself to see if I could speed the box up and help others make a better informed choice. I quickly found out that I have ten year old class 2 cards that outperform those so called "fast" class 4 cards. So should we all be using class 2 cards because in one case a class 2 card was faster than a class 4? "NO!" Of all the cards I have tested, those Class4 cards that came with my B+ are the SLOWEST ones I have tested. After testing quite a few cards on the RPiB+ and RPi2, my best results in boot times, App launching, overall system responsiveness and disk throughput have been with Class 10 UHS-1 cards and my boot times are in the 20-30 second range depending on if I boot to the command line or gui. Sure, the RPis are not UHS, but the design and speed of these newer cards provide tangible, reproducible results that can make a night and day difference in the RPi performance and overall experience.
I have been posting my results from both the B+ and Pi2 on the thread "SD Card Benchmarks" http://www.raspberrypi.org/forums/viewt ... =63&t=4076 and am also trying to get people on that thread to use a "common test" that is run on the RPi so the results should be reproducible and reflect how the cards perform in the REAL RPi world. The Pi2 generally has slightly higher results than the B+ for the same card. If you would like to compare cards, Please compare Raspberries to Raspberries instead of Raspberries to Apples or Windows. And please, base it on Factual testing on a Raspberry Pi. Enough of the "MYTH". Proceed with the facts!

Cheers!
LitterBugs


Hackin' since mid 70's, Unix geek since the mid 80's, Network geek since the 90's, and I still remember upgrading from 1K of system RAM to 4K wondering how could I ever fill all that space up.

[fruitoftheloom]

WHATEVER

[Ian Mac]

I'm reading the Quick Start Guide from the HELP section on the Raspberry Pi website

I'm reading the "Plugging in your Raspberry Pi"
"Before you plug anything into your Raspberry Pi, make sure that you have all the equipment listed above to hand. "

I'm thinking that I have all the physical ingredients to run the Pi.

I have a 16GB class 10 SD card and a Raspberry Pi 2 Model B 1GB card.

"Then follow these instructions:"
" 1. Begin by slotting your SD card into the SD card slot on the Raspberry Pi, which will only fit one way."

Question one: where do I slot my SD card in? Why isn't there a diagram to help me?

Well thanks to the info here I realise that I have to have a MicroSD card, but there is no info that I am aware of that tells me this on a marketting site or indeed, as I am pointing out above, on the Raspberry Pi website itself.

[W. H. Heydt]

It's probably an assumption--and, yes, I know why such assumptions are bad idea in beginner guides--that pretty much everyone by now knows how to put an SD/microSD card into a slot.

Just for clarity, the labeled side of the SD/microSD card goes *away* from the circuit board. That is, since the card holder is on the bottom of the board, the card is put in "upside down" (when viewed from the top of the board). This means that the electrical contacts on the card go toward the circuit board.

[Tom_A]

Thanks very much. My microsd is a class 10 so the RPI is doing the best it can.

Actually Class 4 or 6 are more suited to the RPi I/O, many posts on this subject

This mythical information about class 4 and 6 cards being better suited for the RPi is not based on fact and should stop being perpetuated without details to back it up. Sure there are a large number of posts stating it, but that does not make it a true statement.

Originally there were many reports of issues with SD cards corrupting, especially if using an overclock so I've been moving the OS to USB and running off that after boot for stability since I started with the Pi. I think that problem may be solved now, but I suspect the old card slot may have contributed to the issue. As far as speed goes, I did some tests after updating to a Raspberry Pi B2 and:

/dev/mmcblk0: #Class 10 card
Timing cached reads: 844 MB in 2.00 seconds = 422.08 MB/sec
Timing buffered disk reads: 54 MB in 3.01 seconds = 17.95 MB/sec

/dev/sda1: #USB 3
Timing cached reads: 834 MB in 2.00 seconds = 417.15 MB/sec
Timing buffered disk reads: 94 MB in 3.00 seconds = 31.29 MB/sec

A SanDisk USB 2 drive I tested was around 20 for timing buffered disk reads. I know that the port is only USB2, but if you get a good USB 3 drive, the memory fast enough that the only bottleneck you will see is the USB speed.

I'd be happy with a Raspberry Pi that didn't even have a card slot and just booted from USB without requiring /boot be on a SD card, even without another USB port included.