Parallels uses a stupid method to remember the selected Boot Camp disk. It uses the disk# device names.
Code:
:~ joevt$ ls /dev/disk?
/dev/disk0 /dev/disk1 /dev/disk2 /dev/disk3 /dev/disk4 /dev/disk6 /dev/disk7
If you have more than one disk attached to your Mac (especially Mac Pros) then the device names change every time you reboot the Mac (possibly because the kernel is multi-threaded and disk devices may be added in any order).
They need to do some research and come up with a better method or combination of methods to identify a disk.
- hard drive model (but some people may install more then one hard drive of the same model).
- partition layout (but some people may have disks of the same size with the same number and size of partitions).
- volume IDs (but some people may clone a volume without making a new volume ID, plus volume IDs can only be obtained from known file systems).
- volume names (but some people may have disks with the same volume names).
- hard drive location (firewire port/usb port/drive bay number) (but some people may move a hard drive to a different location).
- an Apple alias (but who knows how smart aliases are and the drive the alias points to needs to be mounted before the alias can be used).