Re: Netbooting a PDP-11 - VMS

This is a discussion on Re: Netbooting a PDP-11 - VMS ; On Wed, 4 May 2005, Tim Shoppa wrote: > > What OSes supported netbooting? > > This was most commonly used for RSX-11S applications. Custom > applications outside the 11S kernel exist too. True. I don't think I've seen anything ...

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Thread: Re: Netbooting a PDP-11

  1. Re: Netbooting a PDP-11

    On Wed, 4 May 2005, Tim Shoppa wrote:

    > > What OSes supported netbooting?

    >
    > This was most commonly used for RSX-11S applications. Custom
    > applications outside the 11S kernel exist too.


    True. I don't think I've seen anything else than RSX-11S as netbooted.

    > > What was required on a host to support this?

    >
    > MOP. The hardware address of the Ethernet controller on the 11S node
    > identifies which machine it is. I've seen RSX-11M, VMS, and even a few
    > Unices (not all Ultrix!) used. On a DEC system MOP usually implies
    > DECNET installed but not always.


    NetBSD ships with a MOP daemon for instance. It's used to boot VAXen over
    ethernet as well.

    > > Did this include the ability to run diskless and
    > > get all of their storage from another machine?

    >
    > Typical RSX-11S applications don't really have a file system, just a
    > kernel and an application.


    More or less true. RSX-11S systems don't have any local mass storage, and
    thus no local file system. RSX-11S systems are basically memory only.
    However, RSX-11S systems can access files over DECnet (DAP). Also, tasks
    can be loaded and checkpointed over DECnet (HLD). And you can also get
    crash dumps of RSX-11S systems uploaded to a file on another host.

    > If you're familiar with DEC Terminal servers booting from a host via
    > MOP, the process is very similar.


    It's the same. :-)

    Johnny

    Johnny Billquist || "I'm on a bus
    || on a psychedelic trip
    email: bqt@update.uu.se || Reading murder books
    pdp is alive! || tryin' to stay hip" - B. Idol
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  2. Re: Netbooting a PDP-11

    On Wed, 4 May 2005 17:06:49 +0200 (CEST), Johnny Billquist
    wrote:

    >On Wed, 4 May 2005, Tim Shoppa wrote:
    >
    >> > What OSes supported netbooting?

    >>
    >> This was most commonly used for RSX-11S applications. Custom
    >> applications outside the 11S kernel exist too.

    >
    >True. I don't think I've seen anything else than RSX-11S as netbooted.


    I wrote a MOP network boot for one of my systems a few weeks ago.

    I fudged the MOP code in my Windows ethernet server -- pretty simple
    stuff although working out the magic numbers was a bit tedious.

    The PDP-11 end was a bit trickier because I decided to put the boot
    code in an RT-11 driver which limited the code to the 200 or so words
    available for such things. But I managed to squeeze it in.

    I can now boot a "diskless workstation" (which means the machines
    where the disk has blown up or a new system) via the BDV boot roms or
    with an RT-11 style BOOT command.



  3. Re: Netbooting a PDP-11

    > [ MOP daemon ]

    I should point out that MOP also was designed to work over non-Ethernet
    interfaces, e.g. sync and async ports that're also supported by
    DECnet/DDCMP, and if I look in the spec I see stuff like token ring and
    FDDI too that I've always avoided touching or even thinking about :-)

    As long as I'm racking my brain, I seem to recall DEQNA/DELQA
    interfaces had on-board firmware that helped a lot in writing a MOP
    boot. Wasn't there some special command that caused the interface to
    do a DMA transfer containing the MOP boot into the host's memory or
    something else funky?

    Tim.


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