From: Paul Hartman <paul.hartman+gentoo@gmail.com>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] Strange partition on USB stick
Date: Tue, 4 Oct 2011 14:36:06 -0500 [thread overview]
Message-ID: <CAEH5T2PK8h=dj+D9Av8mcsVD_E8XvYFokiYjjxVG3a+pfdV7+w@mail.gmail.com> (raw)
In-Reply-To: <201110041939.30850.michaelkintzios@gmail.com>
On Tue, Oct 4, 2011 at 1:39 PM, Mick <michaelkintzios@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.
next prev parent reply other threads:[~2011-10-04 19:37 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-03 22:15 [gentoo-user] Strange partition on USB stick Mick
2011-10-04 3:39 ` Adam Carter
2011-10-04 5:18 ` Mick
2011-10-04 5:27 ` Paul Hartman
2011-10-04 6:53 ` Alan McKinnon
2011-10-04 15:57 ` Mick
2011-10-04 6:58 ` Mick
2011-10-04 16:18 ` Paul Hartman
2011-10-04 18:39 ` Mick
2011-10-04 19:36 ` Paul Hartman [this message]
2011-10-04 21:35 ` Mick
2011-10-07 22:09 ` Klaus Müller
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