The DISKQUOTA CREATE command creates a quota file for a volume
    that does not currently have one.

    Only one quota file, [000000]QUOTA.SYS, can be present on
    any volume or volume set. As soon as you create a quota file,
    establish default values for quotas and overdrafts by adjusting
    UIC [0,0] with the DISKQUOTA MODIFY command. When a disk has
    existing files, use the DISKQUOTA REBUILD command to have SYSMAN
    update the quota file to contain current usage values.

                                   NOTE

       VSI recommends that you do not create and enable a quota file
       on the system disk unless users are allowed to create files
       on that disk.