LinLog

Here's a weird one. For some reason, my Digitalway MPIO FL100 MP3 player can't see files that are copied onto the removable SD card from Windows. But files copied from Linux show up fine. Is it just me, or does that seem a little backwards?

What happened was that I wanted to listen to a few podcasts this morning. I didn't feel like running downstairs to get the SD card out of the MP3 player, and I didn't want to download them from work, so I just dumped the files on my USB thumb drive before I left the house. When I got to work, I whipped out my portable USB SD card reader, copied the files from the thumb drive to the SD card, and slapped the SD card back in my MPIO. I turned the player on, started browsing the playlist and...nothing. The files just weren't there.

My frist thought was that something must have gone wrong. Maybe I disconnected the card too early and the files didn't copy. So I hooked the SD card back up to my Windows XP workstation and checked. Hmm.... The files were definitely there. Were they corrupt? Didn't seem to be. The file sizes looked right and they played in Windows Media Player.

Maybe it was because the card was almost full. It's a 1GB SD card and there were only 6MB left. Maybe the MPIO can't quite address a full gigabyte. So I moved the files I was trying to play off the card, deleted a few old files, and moved the new ones back. OK, now I've got about 50MB free, which has always been enough before. But when I plugged the card back into the MPIO, it was still a no-go.

After a few more unsuccessful variations on this same process, I started to wonder if the problem was with the SD card reader or even Windows itself. After all, this never happened with my internal SD card reader on my home Kubuntu system. So just for the heck of it, I fired up a copy of Kubuntu running in VMware. I plugged in the SD card reader, moved the MP3s off the card, unmounted and remounted, and moved them back on. This time, when I put the card back in the MPIO, it saw the files. I was able to select them in the playlist and they played perfectly.

At this point, the question is: What the hell happened? According to fsck.vfat, the SD card uses a FAT32 filesystem with long filename support and doesn't show any errors. Theoretically, Windows should be able to read and write that with no problems. And it can - but not in a way the MPIO can read. Is there some extension to FAT32 that Windows uses but Linux and the MPIO don't? Is this due to some implementation-specific detail where the MPIO agrees with Linux but not Windows? There's got to be some rational explanation for this. Does anybody have any ideas?