/GPT (default for Integrity servers)
       /NOGPT (default for Alpha)

    Applies to Files-11 On-Disk Structure Level 2 (ODS-2) and Level 5
    (ODS-5) disks only.

                                   NOTE

       If you specify /GPT, the disk might not mount on some
       systems running older versions of OpenVMS.

    When /GPT is specified, the system file [000000]GPT.SYS is
    created. GPT.SYS contains partition/boot information needed
    by the IA64 console software. (GPT is an abbreviation for GUID
    Partition Table, where GUID stands for Global Unique Identifier.)

    The BACKUP utility recognizes GPT.SYS and maintains its contents
    in a save/restore operation.

    If /NOGPT is specified, the pre-Version 8.2 VBN layout of
    [000000]INDEXF.SYS is used. The VBN layout is described in
    the Guide to OpenVMS File Applications and in VMS File System
    Internals by Kirby McCoy (ISBN 1-55558-056-4, 1990).