Grub is asking which disks to install itself to:

 [ ] /dev/sda (200049 MB; ST9200420ASG)  
 [ ] - /dev/sda1 (254 MB; /boot)  
 [ ] /dev/dm-1 (191667 MB; kwarm-root)

Should I install it to the overall disk (/dev/sda),
or to the boot partition (/dev/sda1, but what does the
"-" mean in that entry?)?