Beaglebone Buffer I/O issues

I saw some benchmarks from TI for AM335X EVM and NAND flash was slower than SD ?!? I have another SoC were Micron NAND SLC is used and is much faster than SD card.

Hope the eMMC cape is SLC based :slight_smile:

BTW. If you need industrial-grade SLC SD cards this is what I´m using on 500+ BTS (hot environment)

http://www.atpinc.com/p2-4a.php?sn=00000391

I saw some benchmarks from TI for AM335X EVM and NAND flash was
slower than SD ?!?

Link?

I have another SoC were Micron NAND SLC is used
and is much faster than SD card.

Performance depends on a whole lot of things, simply making comparisons
of the speed of SD cards and raw NAND isn't very useful without knowing
all the dependent things (like manufacturer, bus interface, clock rates,
controller algorithms, file system, etc).

Hope the eMMC cape is SLC based :slight_smile:

I don't believe it is. Even so, the controllers in eMMC devices are
usually rather sophisticated, especially compared to SD cards. eMMC
controllers probably skew more towards acting like SATA SSD controllers
than like SD card controllers.

eMMC plays a different role than SD does for the "normal use" insomuch as
cost has a different priority in relation to other things, like wear
leveling. Since eMMC isn't easily user replaceable (few users own hot
air rework stations :)), having it wear out would be rather bad. SD
cards are cheap and easy for a user to replace, having them wear out
isn't as big of a deal.

Plus, 90%+ of the time, SD cards are used as photo or video storage
where write counts rarely reach 10k or higher over their life. There's
really no incentive to optimize for high write counts for SD
manufacturers.

-Andrew

I saw some benchmarks from TI for AM335X EVM and NAND flash was
slower than SD ?!?

Link?

http://processors.wiki.ti.com/index.php/AM335x-PSP_04.06.00.07_Features_and_Performance_Guide#Performance_Benchmarks_2

3.4MB/s for NAND
19.2MB/s for SD (SD Card (Sandisk Extreme 64G Class 10 SDXC card)

Take 9MB/s for a cheap SD card still is a 3:1 ratio :frowning:

I have another SoC were Micron NAND SLC is used
and is much faster than SD card.

Performance depends on a whole lot of things, simply making comparisons
of the speed of SD cards and raw NAND isn’t very useful without knowing
all the dependent things (like manufacturer, bus interface, clock rates,
controller algorithms, file system, etc).

This is based on tipical DreamPlug/GuruPlug NAND (Micron SLC) using UBIFS vs SD SLC (ext3) card rates on the same HW. Sure, Marvell SoC is quite different than TI SoC.

Hope the eMMC cape is SLC based :slight_smile:

I don’t believe it is. Even so, the controllers in eMMC devices are
usually rather sophisticated, especially compared to SD cards. eMMC
controllers probably skew more towards acting like SATA SSD controllers
than like SD card controllers.

eMMC plays a different role than SD does for the “normal use” insomuch as
cost has a different priority in relation to other things, like wear
leveling. Since eMMC isn’t easily user replaceable (few users own hot
air rework stations :)), having it wear out would be rather bad. SD
cards are cheap and easy for a user to replace, having them wear out
isn’t as big of a deal.

Hope to get one of those NAND/eMMC capes soon to play. I got some Micron 16b NANDs but I have to get the PCB done and that probably will be later than those new capes :slight_smile: