Hi.

Well, /proc/mounts will always show the device name used to initiate the mount. That is either the device nodes name you specified in /etc/fstab or the name you gave on the commandline for "mount /dev/<device> /<mountpoint>. It couls even show /dev/rootpartition as the device if that node existed and had the correct device numbers (major and minor) and possibly also if that is just a symlink to the actually used device node.
/proc/ide* will show the linux standard names for the devices. It will always show hdb for the second drive on the first bus and hdc for the first device on the second bus, no matter how the device nodes in /dev/ where named.

cu,
sven