Conference 7.286::fddi

971.0. "disconnected DEMFA " by COMICS::WEBSTERC () Wed May 26 1993 09:55

    
	Is this a DTSS or an FXdriver problem ? It would appear
    	that an unconnected DEMFA will still clock fatal errors, 
    	(note 521, 864) and also cause some problems, but it does 
    	not seem that this is documentated anywhere for customers.
    
    	Colin
    
    
           <<< NOTED::DISK$NOTES4:[NOTES$LIBRARY_4OF4]DTSS.NOTE;3 >>>
                                 -< DTSS_NOTE >-
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Note 325.0                      DTSS$SERVER crash                      3 replies
BRSDM::BOKOR "Big Browser"                           11 lines  15-DEC-1992 03:47
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We recently migrated our systems to 5.5-1, plus Decnet Vax Extension. All systems
work OK, except one, where DTSS keeps crashing rapidly after its startup. One 
specific thing on this system is a FDDI interface (I've read some previous -old- 
notes  about problems with two Ethernet interfaces...)

I've put the DTSS$SERVER.DMP file in BRSIS8:: . Could somebody have a look and 
give me a hint ? 

Thanks.

Charles.
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Note 325.1                      DTSS$SERVER crash                         1 of 3
TUXEDO::YANKES                                        4 lines  29-DEC-1992 14:41
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    	Ok, we'll have someone take a look at it and get back to you.
    
    						-craig
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Note 325.2                      DTSS$SERVER crash                         2 of 3
BRSDM::BOKOR "Big Browser"                            9 lines  30-DEC-1992 08:03
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Well, in order to be complete, I have to add that the FDDI interface was 
installed, but not yet connected (system was still connected via Ethernet).

Since saturday, the switch over to FDDI was made,...and DTSS seems to work OK
now. This would confirm that the problem was the multiple network interface... 
(we have an MFA and an MNA, now the MFA is on and MNA if off). Do you think this 
make sense ?

Thanks...
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Note 325.3                      DTSS$SERVER crash                         3 of 3
COMICS::WEBSTERC                                     16 lines  26-MAY-1993 10:31
                      -< Has there been a fix for this? >-
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    	Sorry to revive this entry after such a long time
    
    	I have a report of the same problem, i.e. if the fddi interface
    	is not connected or no loopback then DTSS dies. It seems that this
    	happens after the fxa0 device is polled and a fatal error
    	controller error received.
    
    	Whilst we know what the fix is, ( connect the thing!), is it not
    	possible that a "normal" demfa problem could cause the same
    	problem?
    
    	It does not seem reasonable that an error on one media should spoil
    	it for all! 
    
    	Colin
    

If the DEMFA is left unconnected there is a possibility that it could crash the
system.   What the whole problem boils down to is that the driver is trying
to read a DEMFA CSR while the adapter is resetting and the result is a NXM 
error which causes the system to crash.  The adapter will not reset if connected to the
to the ring or if a loopback is in place, so it will not experience the 
NXM error.

A change was done to the driver to correct this problem.  Contact VMS to find out
what revision has the fix.



Maureen

    
    	Is this the one you mean?
                                                                         
    FXDRIVER, when the FDDI  cable  is  disconnected,  resets  the
    DEMFA  every  5  or  300  seconds.   After  reset, at 1 second
    intervals, it reads the XPST register  to  see  if  self  test
    completed.   It  should wait the prescribed self test time (10
    seconds) before reading any of the device registers or risk an
    XMI error that would crash the system.
    
    Colin