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Conference 7.286::fddi

Title:FDDI - The Next Generation
Moderator:NETCAD::STEFANI
Created:Thu Apr 27 1989
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2259
Total number of notes:8590

521.0. "Strange problems with a DEMFA ?" by COMICS::WOODWARD (Smile!) Mon Mar 30 1992 11:00

Any ideas about this one .....

The customer has a VAX 9000 with DEMFA. A while ago the demfa was disconnected
from the FDDI and left unconnected. The DEMFA started logging device errors
and after a period of about 28 days and approx 9000 errors the system crashed 
(machine check). The crash pointed towards a DEMFA problem. This in itself seems
a little odd, but the same thing has happened on a second 9000/DEMFA, again at
about 28 days and ~9000 errors. The workaround seems to be to install a loopback into the
demfa - it then stops logging device errors and we think (wait 28 days to
check) it will stop the crash. The "last fatal error code" for the device is
00000003 (transmit timeout).
 
Can anyone suggest what may be happening here - because I don't believe there
should be any problem having the DEMFA disconnected from the LAN.

Thanks,

Steve
T.RTitleUserPersonal
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521.1file a QARSTAR::SALKEWICZIt missed... therefore, I am Mon Mar 30 1992 14:1910
    With the FDDI cable unplugged from the DEMFA, the driver will declare
    a fatal error every five minutes. This error is declared when the FDDI
    ring remains unavailable for five minutes, but the device seems to be
    operating correctly otherwise. It is declared to avoide the case where
    the device gets hung reporting FDDI ring unavailable.
    
    Why the crash after 9000 errors and 28 dyas I don't know. Sounds
    like a QAR should be filed with the dump.
    
    
521.2KONING::KONINGPaul Koning, NI1DMon Mar 30 1992 16:209
You certainly want to make sure that network management can tell the
device isn't connected, but calling that a "fatal error" is NOT right.

Such terminology suggests defective hardware or internal bugs, and is
not appropriate for what may be either a cabling problem, or even an
intentional setup (hardware installed prior to availability of what it's
going to plug into).

	paul
521.3Yes,..STAR::SALKEWICZIt missed... therefore, I am Tue Mar 31 1992 12:4012
    Agreed, and actually it should not be being logged as a fatal error.
    
    The resetting of the board will happen. But there is no need
    for fatal errors to be logged. That logging should be disabled
    in the driver,.. but there is a bug there. 
    
    The crash is still interesting because the system should be able
    to reset the device and log errors indefinitely, so please
    file the QAR anyway..
    
    							/Bill
    
521.4help DEMFA failoverSUBWAY::HILTONthe light at the end of the tunnel is an Oncomming..(crunch)Wed Apr 01 1992 14:149
    Help Help.\
    
    If I have two DEMFA controllers on a 6420, and I run LAT on one of
    them... IE: DEMFA unit A is running LATmaster 
    	        DEMFA unit A kicks the big one.
    		does LAT switch over AUTOMATICALLY WITHOUT session loss
    		to DEMFA unit B ?
    
    				send mail to SUBWAY::HILTON  thanks!!!!!
521.5wrong conference?STAR::SALKEWICZIt missed... therefore, I am Wed Apr 01 1992 17:075
    I don't have the pointer,.. but I''m sure theres a better place to ask
    this question ,.. like a LATMASTER conference...
    
    								/Bill
    
521.6I have the dump if anyone wants a peek...KERNEL::LLOYDADon't worry... Be Happy ;^)Wed Apr 08 1992 13:367
    re: .3
    
    Bill,
    
    Why use a QAR ? I thought a QAR was for field test problems only ?!?!
    
    Alan.
521.7QARa are your (and my) friendSTAR::SALKEWICZIt missed... therefore, I am Wed Apr 08 1992 14:2811
    NO ,.. QARs are for released software as well,... and the reason to use
    them is that it convinces people that a problem is real. Believe it
    or not, its eaiser for me to make changes to my driver if I have
    QARs,.. because in managements eyes I am then fixing a "real"
    problem,.. as opposed to one I dreamed up or one that I just
    fell like fixing,...
    
    Like the man says: When the going gets weird, the weird turn pro
    
    							/Bill