Re: need a bit of early boot help

[Anders Magnusson <ragge%tethuvudet.se@localhost>]

    Good morning!  11/780, cool!  Long time since I last used one of
    those.

Den 2025-11-11 kl. 04:13, skrev Dave McGuire:

>       
>         Hi folks, I'm working on a VAX-11/780.  I'm (forgive me) trying
>       to get VMS 4.7 up and running on it, from a known working (on an
>       11/750) system disk, and it hangs right after printing the banner.
>       
>       
>         As a diagnostic tool for now, I wanted to boot NetBSD 1.6.1 on
>       it, to see if it'd get any further.  It stops in a suspicious
>       place: Right after printing "root file system type: ffs", on the
>       next line, it prints an 'S' and hangs.  The processor is still in
>       run state.
>       
>       
>         In an instance of simh with a system configured identically to
>       my hardware, I see that 'S' is the first character of this date
>       stamp:
>       
>       
>       Sun Nov  9 22:05:50 GMT 2003
>       
>       
>         ...which is the line immediately following "root file system
>       type: ffs".
>       
>       
>         I could start digging, but I figured I'd ask for some quicker
>       help here.  What prints that date stamp?  What (in NetBSD) could
>       cause the machine to hang right there, does anyone have any idea?
>       
>     
    Note:  Simh for 11/780 is implemented significantly different from a
    HW perspective than the "real thing".
    
    Console output on the 11/780 is implemented by internal registers
    that send the data to the pdp11 which is the console processor.
    
    The kernel printout (devices etc...)  are printed by checking the
    ready flag and then printout the data:
    
            while
      ((mfpr(PR_TXCS) & GC_RDY) == 0) /* Wait until xmit ready */
                      ;
              mtpr(ch, PR_TXDB);      /* xmit character */
      
    But; when the OS start to run then the output will be
    interrupt driven.  In your case it sounds like after the first char
    written no interrupt is generated that tells the pdp11 can receive
    another char.
    
    Since you have a similar problem with VMS I would recommend start
    running the diagnostic program to see if something is broken.  Not
    uncommon on those machines :-)
    
    -- R