Reliability of USB-based filesystems? Lack thereof?

[Christopher Browne]

I have been running into a problem lately which I thought I'd "toss
over the wall" to see if others have experienced similar...

I have been having *terrible* troubles trying to copy files of any
material size (e.g. - such as videos and such) onto USB-based devices,
notably USB memory sticks and onto SD cards mounted via USB.

I copy files over, and there are two tendancies:

1.  Frequently, I run out of disk space on the device, even though
there's certainly plenty of room left.

2.  After completing copying, I unmount the filesystem (which takes a
while, due to flushing out updates), and when I remount, the
filesystem tends to be pretty corrupt, with wacky directory entries
containing control characters.

I'm not at all sure that this is a USB-relevant issue; what I am
getting mighty suspicious of is that perhaps I'm blowing up the VFAT
filesystem (fyi, I keep having to rebuild the filesystems when I
attempt a retry).

All seems to be OK if I keep to moderate file sizes (e.g. - a few MB
in size); everything seems to go bad when file size grows to 100's of
megabytes.  That's not formal "troubleshooting info;" that's more like
an anecdote.

What seems rather interesting is that I observe this in a
cross-platform fashion; I see this phenomenon both on Linux and on
MacOS.

A quick google finds the following (reported on Darwin, I'm not sure
if this is with "Hackintosh" or with "just Darwin"; don't think that's
too relevant...)
http://forum.insanelymac.com/index.php?s=fd9e8e56f8887e542acf2e01e7ea6917&showtopic=57523&st=0&p=410781&#entry410781

It is suggested that the problem might be insufficient power to the
USB devices; that seems implausible when I'm mounting them on a
desktop box where there should surely be plenty of power.

I have been seeing this phenomenon for a while, on a variety of hardware.
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"The definition of insanity is doing the same thing over and over and
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