Mac in sleep and USB flash drive

[inflynx]

Given:
MacBook Pro, USB flash drive

Conditions:
1. Plug flash drive into MacBook USB port
2. Open some documents from the flash
3. Leave MacBook until it goes to sleep

Effects:
When awoken USB is unmount and all opened documents are frozen.
Have to unplug USB flash and plug in back again.

Questions:
Is it how it is supposed to be?
How do you prevent USB from unmounting when MacBook goes into sleep mode?

 

[mad jew]

You can't prevent it from unmounting but you could set the MacBook to not fall asleep.

 

[inflynx]

Is there a way then to set some sort of automatic mount on when awoken?