sd card management

[Sarge, USMC]

if I use the astro file manager and go to the sdcard folder, open it up, I see another sdcard subdirectory......so it's sdard/sdcard/music....pictures....etc.............but if I plug this puppy into the desktop to look at the dir structure of the device, the dir is sdcard/muic, pictures, etc.........know what I mean? Viewing it that way there is no sdcard subdir of the sdcard root. Wat gives?