Three small things have led up to this post
So, time to do a little digging ....Firstly Vista backup uses two formats, neither of which are BKF. When I was told that a user couldn't restore from BKF, my first thought was "user error" followed by "Surely we wouldn't ...". There will be a downloadable tool to READ but not write backups made from older operating systems. This leaves the question "will the new backup be back ported to XP and Windows 2003" nothing I've seen suggests that it will.
Now, the two formats. Windows Vista can do a "CompletePC" backup. This makes a VHD file. VHD is the disk image file used in Virtual PC and Virtual server (and which will be carried forward in Longhorn's Windows Server Virtualization). There are two key things about this
It will be interesting to see what additional tools appear to work with VHD format files - in doing a search for existing tools I found a post of John Howard’s that links to Gilles Vollant’s Winimage , but I’d like to mount VHD’s as drives (there is an internal Microsoft tool for this), and I’d also like a utility on a boot disk which creates VHDs - again for physical to virtual migration. Automated Deployment Services (ADS) which we use in the Virtual server migration tool kit (VSMT) has another kind of imaging technology - I wonder if that too will change to VHD, because I think it might be one imaging format too many.
So much for CompletePC Backup. The other backup uses volume shadow copy and is intended to be run regularly. Backup has been re-worked, out goes support for tape drives, in comes support for optical disks. The aim is to get more people to do more backups, more often and the side effect is more disk space is going to get used. Because the backup is shadow copy based it is quite simple to give "point in time restores" - without the user having to track full and incremental back-ups. Vista keeps a copy of the back-up catalog locally and this is what enables point of time restores.
There is a great "Backup And Restore In Windows Vista And Windows Server Longhorn." slide deck from Winhec which explains how it all works.