HP-UX 10 and 11 also have the Logical Volume Manager (LVM). The way it works is that the sysadmin can designate a disk or group of disks to form a physical volume group, and then up to eight partitions called logical volumes can be formed from that group. If there is free space in the physical volume group, then a logical volume can be extended using the "lvextend" command while it is umounted. However, a logical volume cannot be reduced without losing the data on it. The LVM is not as good as Partition Magic in this respect; Partition Magic can reduce the size of your Windows partition while running under Windows.