SYS$DIAGNOSTICS.SYS is an optional hardware diagnostics partition
    found on various OpenVMS I64 system disks. It is comprised of a
    FAT partition, potentially containing various diagnostics files.

    The location of this file must be registered in the bootblock
    structures using the DCL command SET BOOTBLOCK or by invoking
    the sys$setboot.exe image. If the file is deleted, then the
    bootblock must also be updated by invoking SET BOOTBLOCK or
    sys$setboot.exe.

    This section contains both an example and a detailed description.

1  –  Example

 $ RUN SYS$SYSTEM:EFI$CP
 EFI$CP> initialize sys$common:[sysmaint]sys$diagnostics.tmp -
   /device_alias=efidiag:/create/size=256000/contiguous -
   idiag /nolog
 EFI$CP> exit
 $ SET FILE/NOMOVE SYS$COMMON:[SYSMAINT]SYS$DIAGNOSTICS.TMP
 $ SET BOOTBLOCK SYS$SYSDEVICE:/I64

2  –  Description

    The example creates and initializes an empty hardware diagnostics
    partition SYS$DIAGNOSTICS.TMP within the cluster-common area of
    the target system disk. (The actual diagnostic partition name is
    SYS$DIAGNOSTICS.SYS.) The diagnostic partition is comprised of
    256,000 blocks, and is subsequently registered within the OpenVMS
    I64 bootblock structures using the DCL command SET BOOTBLOCK.

    As with the SYS$EFI.SYS example, this example deliberately shows
    the hypothetical partition filename SYS$DIAGNOSTICS.TMP and not
    the actual partition SYS$DIAGNOSTICS.SYS partition filename.
    Use of the actual partition name would replace any existing
    diagnostics partition.

    When a new diagnostic partition is created, or is relocated on
    the system disk, or is deleted, use the SET BOOTBLOCK command
    or invoke the sys$setboot image directly to update the OpenVMS
    I64 bootblock and related structures accordingly. Use the SET
    FILE/NOMOVE command to prevent a defragmentation tool from
    erroneously relocating the file.