Timeshift
Means the box is permanently recording so that you can rewind a program your watching
As far as I know when the program is over it deletes the recording and starts again recording the program that is now showing
so if you try to rewind the program that has only been showing for 2 mins then you can only go back 2 mins but if it was near the end you could go all the way back but when its over the recording will be gone
Obviously you would need a hard drive installed for this to work
Happy Christmas