/etc/mtab is created automatically and represents all mounted filesystem. If you would like to mount a filesystem on bootup, you need to add this to /etc/fstab.
The syntax is little different from the commend you would use on command line. In one line, you put information on
1. device (/dev/hdb6)
2. mountpoint (/home)
3. filesystem (ntfs)
4. options (auto,users,umask=000)
5. some special info, how fsck has to treat the partition (mostly 0 0)
See man fstab and man mount for further details.