VMS Help EXCHANGE, COPY, Qualifiers, /BOOT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /BOOT[=nn]

    Copies bootstrap information from a monitor and the handler files
    to blocks 0 and 2 through 5 of an RT-11 volume, permitting you to
    use that volume as a system volume. The COPY/BOOT operation does
    not create any files on the volume; it is intended only to create
    bootable RT-11 systems.

    The /BOOT qualifier implies /VOLUME_FORMAT=RT11 for both input
    and output specifications. The output device can be omitted, as
    it is assumed to be identical to the input device. You cannot
    combine the /BOOT qualifier with qualifiers other than /LOG.
    The COPY/BOOT command requires that both the input and output
    devices be the same volume or virtual device. The file name of
    the desired monitor must be specified as the input specification.

    RT-11 Version 1.0 through Version 3.0 monitors had the system
    device handler linked into the monitor image. For Version 4.0
    of RT-11, the system device handler uses the standard device
    handler, and the COPY/BOOT command must dynamically link the
    handler into the bootstrap area. COPY/BOOT finds the default
    handler for the specific device type and merges the handler with
    the monitor as it is copied to the boot area.

    You can use the two-letter argument nn to override the default
    system device handler. The most frequent use of this option
    occurs when a diskette is mounted in an RX02 drive, and you want
    to create a diskette bootable from an RX01 drive. (The diskette
    must be single density.) The default handler for the RX02 is
    DY.SYS, and the handler for the RX01 is DX.SYS; therefore, you
    would use the command COPY/BOOT=DX to create the bootable RX01
    system diskette. Do not specify /BOOT=nn for Version 3.0 RT-11
    and earlier systems; instead, choose the monitor file DYMNxx.SYS
    or DXMNxx.SYS as the source file.