How to add a disk to a new system without losing the data on it?

[Lowell Gilbert]

Vincent Zee <basics at zenzee.cistron.nl> writes:

> Hello,
> 
> How do I add a disk containing data to a new system without erasing 
> that data.
> 
> I searched the mailinglist and the documentation but could not find 
> information
> for this scenario.
> 
> The system in question is running 4.8
> The disk is coming from a 5.1 system and uses ufs with softupdates.
> The disk has one partition.

UFS1 or UFS2?
4.8 won't understand UFS2...