On Tuesday 04 Oct 2011 20:36:06 Paul Hartman wrote: > On Tue, Oct 4, 2011 at 1:39 PM, Mick <michaelkintz...@gmail.com> wrote: > > On Tuesday 04 Oct 2011 17:18:18 Paul Hartman wrote: > >> You can create a real partition table on that device and reformat, if > >> you want. (Note that some flash-based devices suffer degraded > >> performance if you repartition or reformat them because they come with > >> specially-aligned FAT tables from the factory) > > > > Interesting! I didn't know that. > > > > I have repartitioned USB sticks in the past, but did not notice any > > change in performance - to be honest I didn't measure it. I assume then > > that if I were to re-partition for any reason I would need to stick to > > exactly the same start & finish shown by parted. > > > > Re-formatting it ought to be OK though, as long as the fat16 shown by > > parted is correct. > > I think filesystems other than FAT are aligned well already, assuming > your partitions are aligned, but with FAT there are some hoops you > must jump through. > > There is a tool called flashbench that can test your drive > (destructively!) and figure out the most optimal block sizes. Here's a > great article about it and optimizing USB flash drives in general: > https://lwn.net/Articles/428584/ > > And here is a forum thread about figuring out the FAT alignment: > http://www.patriotmemory.com/forums/showthread.php?3696 > > The SD council makes a tool for MS Windows that optimally formats and > securely erases SD cards. Might be interesting to compare the results > of its format to a standard fdisk and mkfs.vfat in linux. > > One thing I'm going to do next time I get a new SD card or flash drive > is take a snapshot of the boot sector/partition tables/FAT tables so > if I ever want to reformat it to FAT, I can restore the -- presumably > optimal -- factory layout.
Excellent find! I've got some studying to do. Thanks for sharing. :-) -- Regards, Mick
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