Time Machine with only one internal disk Is it possible to use the time machine backup system without an external (or second) HD? 
I know that the protection to disk failure will not be guaranteed anymore, but the file accidental deletion, the wrong edit etc. will be avoided...

Is there a trick to make Time Machine believes that he has a disk dedicated for him to do the job ?

Note : The situation is using a laptop on travel.
You can partition the disk and run the OS on one partition and Time machine on the other.

Disk Utility can repartition without losing data. but as usual take a backup first.