1 /BLOCK_SIZE
       /BLOCK_SIZE=512 (default)
       /BLOCK_SIZE=2048
    Specifies the target block size for the bootstrap device, in
    bytes.
    The 512-byte block size applies for most disk devices. The 2048-
    byte block size typically is used only when writing the boot
    block to specific OpenVMS Integrity servers CD and DVD devices.
2 /Integrity
       /Integrity servers
    Specifies OpenVMS Integrity servers as the target architecture
    for the boot block. The default boot file for OpenVMS Integrity
    servers is SYS$SYSROOT:[SYS$LDR]SYS$EFI.SYS.
3 /PRESERVE
       /PRESERVE=keyword
       /PRESERVE=SIGNATURE
    /PRESERVE=SIGNATURE maintains the existing GUID disk signature
    value. The default is to generate a new signature for the target
    volume.
    SIGNATURE is the only keyword currently supported.