• Re: SIMH + OpenVMS 5.5-2H4 standalone BACKUP: ISO appears as DJAx not DUAx

    From Sam Thomas@sam@noneya.com to comp.os.vms on Thu Dec 18 17:05:41 2025
    From Newsgroup: comp.os.vms

    flexmcmurphy <plica2006@gmail.com> wrote:
    Hello,

    I am installing OpenVMS VAX 5.5-2H4 under SIMH and am confused by how standalone BACKUP assigns device names when booted from installation media.

    This is where I got the ISO from (Server 1)

    Setup (simplified):
    - SIMH VAX (have tried MicroVAX 3900 and VAX 8600)
    - OpenVMS VAX 5.5-2H4 ISO attached as an RQ device (read-only)
    - Booting directly from the ISO into standalone BACKUP

    In standalone BACKUP, the installation media always appears as DJAx
    (device type RA60), not as DUAx, for example:

    Available device DJA3: device type RA60

    Without seeing your setup, I can't tell you exactly why yours
    results in DJA, but here is the relevant parts of the config I
    used to do this exact thing. I don't remember exactly where
    I got the base of my vax.ini, but it was one of the top
    google results.

    set rq0 rauser=8192
    set rq1 rauser=8192
    ### I suspect this is the bit you might be missing?
    ; Configure a CD-ROM drive (RRD40) on disk interface RQ3
    set rq3 cdrom
    attach RQ0 /home/sthomas/vax/oldvax/data/rq0-big.dsk
    attach RQ1 /home/sthomas/vax/oldvax/data/rq1.dsk
    attach RQ3 -r /home/sthomas/vax/oldvax/iso/VMS55.iso

    Cheers,
    Sam
    --- Synchronet 3.21a-Linux NewsLink 1.2
  • From flexmcmurphy@plica2006@gmail.com to comp.os.vms on Fri Dec 26 12:09:25 2025
    From Newsgroup: comp.os.vms

    I think I have figured out what was happening here.
    The device name (DUAx vs DJAx) assigned to the ISO file depends on what
    SIMH version you are using:
    SIMH v4.0-0 maintained by Mark Pizzolato:
    https://github.com/simh/simh
    Open SIMH v4.1-0
    https://github.com/open-simh/simh
    If your ISO file is small enough in size then with SIMH v4.0-0 (Mark
    Pizzolato) you might get the device name: DJA1.
    In my case I am trying to restore the save_set from an ISO of OpenVMS
    v5.5-4H2.
    Because the ISO is only about 204MB SIMH uses its internal logic
    (autosize) to assign the ISO file a device type of RA60 because that is
    the closest DEC device capacity drive that 204MB matches with. This is
    what happens regardless if you start out with this in your ini file:
    SET RQ3 CDROM
    ATTACH RQ3 -r openvms_v5.5-4h2.iso
    So SIMHv4.0-0 responds to a MRSP query from Standalone Backup with a
    deviceID: (DJ - RA60) indicating that the device at that controller is
    a removable device of type RA60. (DJ - Removable, DU Fixed). Standalone
    Backup then uses it's own logic to translate this to a device name
    DJA3.
    If you disable AUTOSIZE then you will get DUA3 as the device name:
    set rq3 cdrom
    set rq3 NOAUTOSIZE
    attach rq3 -r openvms_v5.5-4h2.iso
    This is because SIMH v4.0-0 will now just respond to a MRSP query with
    whatever device type you define in your ini file.
    If you use Open SIMH v4.1-0 you will probably just get DUA3 as the
    device name and not have to disable AUTOSIZE at all. I don't fully
    understand how SIMH and Open SIMH differ in their device detection
    logic but it seems that with Open SIMH if you put this in your ini
    file:
    SET RQ3 CDROM
    ATTACH RQ3 -r openvms_v5.5-4h2.iso
    Then Open SIMH WILL respond to an MRSP query that the device type is
    CDROM and then Standalone Backup will see this as an RRD40 device and
    create the device name DUA3.
    CDROM device are also removable drives but whereas RA60 disks were
    connected to MSCP controllers RRD40 disks were connected to DSA
    controllers where any type of local disk were consolidated under DUAx
    device naming. Not confusing at all!

    Cheers,
    Flex
    -----Original Message-----
    From: Sam Thomas <sam@noneya.com>
    Subject: Re: SIMH + OpenVMS 5.5-2H4 standalone BACKUP: ISO appears as
    DJAx not DUAx
    Date: 18/12/25 17:05:41
    Newsgroups: comp.os.vms
    flexmcmurphy <plica2006@gmail.com> wrote:
    Hello,

    I am installing OpenVMS VAX 5.5-2H4 under SIMH and am confused by
    how-a
    standalone BACKUP assigns device names when booted from installation
    media.

    This is where I got the ISO from (Server 1)-a

    Setup (simplified):-a
    - SIMH VAX (have tried MicroVAX 3900 and VAX 8600)-a
    - OpenVMS VAX 5.5-2H4 ISO attached as an RQ device (read-only)-a
    - Booting directly from the ISO into standalone BACKUP

    In standalone BACKUP, the installation media always appears as DJAx-a (device type RA60), not as DUAx, for example:

    Available device DJA3: device type RA60
    Without seeing your setup, I can't tell you exactly why yours
    results in DJA, but here is the relevant parts of the config I
    used to do this exact thing. I don't remember exactly where
    I got the base of my vax.ini, but it was one of the top
    google results.
    set rq0 rauser=8192
    set rq1 rauser=8192
    ### I suspect this is the bit you might be missing?
    ; Configure a CD-ROM drive (RRD40) on disk interface RQ3
    set rq3 cdrom
    attach RQ0 /home/sthomas/vax/oldvax/data/rq0-big.dsk
    attach RQ1 /home/sthomas/vax/oldvax/data/rq1.dsk
    attach RQ3 -r /home/sthomas/vax/oldvax/iso/VMS55.iso
    Cheers,
    Sam
    --- Synchronet 3.21a-Linux NewsLink 1.2