My guess would be that maybe:

You successfully copied the 120MB file(s) onto the device.

You then tried to copy onto it a file or files that was/were too large
to fit on the device, so the deivice ran out of space before the file
was closed peroperly, leaving the device full, but no partial file
showing up.

Maybe if you remove all files somehow (re-format it?), and copy your files
onto it again but in smaller files, and monitor what free space it reports
after each file has been copied.

Regarding your figure of 484MB : A lot of memory devices these days are
sold as being (e.g.) 512MB, but the MB does NOT refer to (1024*1024) bytes,
but rather (1000*1000) bytes.

Maybe it's not a coincidence, then, that

512,000,000 bytes /(1024*1024) = 488.2 (proper) MegaBytes

I'm pretty sure that I have had 512MB SD flash cards with exactly
this "shortfall problem". They weren't 512*(2^10) bytes, but they were
only 512*(10^6), which as above, is only 488MB.

Maybe in your case, the other 4 MB are used by the FAT (or whatever)
filesystem on there, or maybe some hidden files or something else.

All guesses though.


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.livejournal.com/userinfo.bml?user=fleetie