[Bug 392089] [NEW] Slow USB transfer for FAT32

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This bug is  "spin off" of bug   "file transfers on USB disk are very
slow "

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/197762

I did some tests and found out that when writing to my USB flash disk
the speed is quite low. I observed that the situation is improved (or
rather resolved) if the flash disk is formated as ext3, so this can be a
problem with fat32. I also have an external USB hard disk (NTFS
formated) which seems to work in satisfactory way. This further supports
the fact that the problem affects fat32 formatted disks.

I ran several tests according to
https://help.ubuntu.com/community/DiskPerformance (and also some other
tests). In all cases I made sure that the flash disk was detected as a
high speed device (USB 2.0) and not as a full speed device (USB 1.1)
using the lsusb command.

Since the problem is more obvious for very large files I let dd create a
test file for about 5 minutes, just to be on the safe side.

The facts:

When I generate a load using dd for about 5 minutes the results from dd
are:

FAT32 USB flash disk:    1617933312 bytes (1.6 GB) copied, 305.66 s, 5.3 MB/s
ext3 USB flash disk:       41091136 bytes (41 MB) copied, 3.85154 s, 10.7 MB/s  
NTFS Hard disk:             4294967295 bytes (4.3 GB) copied, 290.644 s, 14.8 MB/s (maximum file size was reached in less than 5mins

The same USB flash disk performs roughly twice as fast on a Windows XP
machine.

The USB flash disk specificstions state that it is able to write at
10MB/sec and read at 15MB/sec


The hardware
M/B -->                   ECS GF7050VT-M5 (nvidia 7050 chipset), with the latest BIOS
USB Flash Disk --> Crucial Gizmo! plus 4Gb (JDOH4GB-730)
Hard Disk -->          Western Digital WD300 connected with no-name IDE-to-USB equipment.


The sofware
Kubuntu Jaunty 64-bit with all the latest updates installed

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

-- 
Slow USB transfer for FAT32
https://bugs.launchpad.net/bugs/392089
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