SUMMARY: Suspend Mode

From: TOBY POTTS (tobypotts@pmsc.com)
Date: Sat Nov 16 1996 - 16:33:21 CST


     I want to thank all those who responded to my question concerning the
     "suspend" mode. Below are the responses I received.
     
     Again, thanks very much to the following:
     Kai O'Yang
     C. Allen
     David J. Knight
     Alfredo Sola
     
     
     
     Toby Potts
     tobypotts@pmsc.com
     
     -------------------------------------------
     
     RESPONSES:
     ----------
     
     I've got a Netra that shows the same behaviour. The reason is that
     when you power off the device, the Sun believes it has received a
     break signal through the serial port. When that happens, it goes to
     prom level. It is, at least for me, a stupid feature to implement;
     even worse, I haven't found a way to disable it :(
     
     Saludos,
     
     Alfredo Sola.
     
     -------------------------------------------
     
     This sounds like normal behaviour.
     David J. Knight
     
     
     -------------------------------------------
     
     Here are some recent posts. Hope this helps: =============
     Subject:
     SUMMARY: Disabling break detection on tty console?
     Date:
     Tue, 29 Oct 96 17:35:06 GMT
     From:
     "Fred Youhanaie" <youhanf@ncp.gpt.co.uk>
     To:
     sun-managers@ra.mcs.anl.gov
     Followup-To:
     "Fred Youhanaie" <youhanf@ncp.gpt.co.uk>
     
     
     
     Hi again!
     
     Appologies for the delay in getting the summary out :(
     
     Many thanks to all those who replied.
     
     A few people recommended reading Hal Stern's primer on async comms,
     while Hal recommended a product sold by Sun 8-()
     
     If anyone wants a copy of Hal's postscript document, please let me
     know.
     
     Summary of the replies follows:
     
     ==============
     I wrote:
     
     We are using Sparc 2 and Sparc 10 workstaions, we have removed the
     keyboard and the screen and are using vt100 consoles.
     
     Does anyone know if it is possible to prevent the sparc desktops from
     dropping to the boot prom when the tty console is removed/reconnected
     or switched off/on ?
     ==============
     From: Stephen Harris <sweh@mpn.com>
     
     Following document (postscript) contains the circuit... Don't ask me
     about it though :-)
     ==============
     From: stern@sunrise.East.Sun.COM (Hal Stern - Distinguished Systems
     Engineer)
     
     sun sells a package called CONSULT-ZSBREAK that does just this; it
     exchanges the "break" sequence for something else.
     
     try calling +1 415 336 2400 for informaiton, or contact your local
     sunservice people.
     ==============
     From: Jim Harmon <jim@telecnnct.com>
     
     We do this by connecting all our Console Ports to a terminal server.
     That way we only need one console device (tty) and all the machines
     stay up as long as the terminal server is running.
     ==============
     From: maclean@cnoc.CS.McGill.CA (Matthew Sams)
     
     There is an rs232 primer written by Hal Stern, I think, of Sun which
     describes how to make an inexpensive device to do this. The paper
     should be available somewhere on Sun's ftp site.
     ==============
     From: David Sinn <DavidS@corbis.com>
     
     Make sure that the serial cable between the two systems only has
     transmit, receive, and ground. The reset occurs because DTR goes away
     or comes back. Change in DTR pauses the system.
     ==============
     From: Kevin.Sheehan@uniq.com.au (Kevin Sheehan {Consulting Poster
     Child})
     
     Yes - there is a hardware circuit you can use to do this, or you can
     patch out the call to the prom in the zs driver on breaks.
     ==============
     
     Cheers
     f.
     --
     Fred Youhanaie | Tel: 0115 943 4030 KE11, GPT Limited
     | Fax: 0115 943 3568 Beeston, NG9 1LA | MNS: 780 4030
     youhanf@ncp.gpt.co.uk | Intl: +44 115 943 4030
     
     Subject:
     SUMMARY: (2) Disabling break detection...
     Date:
     Thu, 31 Oct 96 8:50:32 GMT
     From:
     "Fred Youhanaie" <youhanf@ncp.gpt.co.uk>
     To:
     sun-managers@ra.mcs.anl.gov
     Followup-To:
     "Fred Youhanaie" <youhanf@ncp.gpt.co.uk>
     
     
     
     I've just received the following note from Kevin on my earlier
     posting.
     
     Forwarded message:
     
> From: Kevin.Sheehan@uniq.com.au (Kevin Sheehan {Consulting Poster
     Child}) >
> > ==============
> > From: David Sinn <DavidS@corbis.com> > >
> > Make sure that the serial cable between the two systems only has
> > transmit, receive, and ground. The reset occurs because DTR goes
     away > > or comes back. Change in DTR pauses the system.
>
> This is *NOT* true - only breaks cause the prom problem. DTR works
> just fine. You might want to clear that up before it becomes urban
     legend > territory :-)
     
     I have tested this with a serial cable that only had the three pins 2,
     3 and 7 (ie DB25, 2/3 crossed over, 7 straight through) connected.
     
     I can confirm that even with the 3 wire cable, switching off/on the
     tty still forces the SPARCstation (SS5) to drop to boot prom :-(
     
     Many thanks to Kevin for spotting this.
     
     I also tried a suggestion from Martin Jackson (martinj@ncp.gpt.co.uk)
     which is to disconnect/connect the serial cable with the tty still
     switched on. This works, ie SunOS (Solaris) continues to function :-)
     Thanks Martin.
     
     For now we have taken up Martin's suggestion.
     
     Cheers
     f.
     --
     Fred Youhanaie | Tel: 0115 943 4030 KE11, GPT Limited
     | Fax: 0115 943 3568 Beeston, NG9 1LA | MNS: 780 4030
     youhanf@ncp.gpt.co.uk | Intl: +44 115 943 4030
     
     ====
     Best regards,
     
     Cola Allen
     
     
     --------------------------------------------
     
     Sure it's related. For all unix boxes, the machine stops when the
     console is off, because the console will send a BREAK during switch
     off and the machine will go into prom mode at once.
     
     There's a FAQ on how to make your own cable so that even switch off
     console machine still runs.
     
     Kai O'Yang
     
     --------------------------------------------



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