Xref: utzoo comp.protocols.nfs:422 comp.dcom.lans:3497 comp.protocols.tcp-ip.ibmpc:1707 Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ames!apple!bbn!bbn.com!clements From: clements@bbn.com (Bob Clements) Newsgroups: comp.protocols.nfs,comp.dcom.lans,comp.protocols.tcp-ip.ibmpc Subject: Ethernet cards, PC/NFS, DS8390 Message-ID: <46100@bbn.COM> Date: 26 Sep 89 18:47:17 GMT Sender: news@bbn.COM Followup-To: comp.dcom.lans Lines: 52 I've just wasted a fair amount of time chasing a problem. I'll briefly summarize it, to try to save others the time and pain, and then ask a question. On an IBM-PC using PC-NFS, I have been getting a steady low level of obscure errors from the Microsoft Linker, and occasionally an error from the C compiler, caused by non-repeatable data errors. They recently became more frequent and I decided to track them down to see whether I had a sick PC or network or a conflicting TSR or what. I switched PC mainframes from a 386 to a 286. Problem still there. Reinstalled PC-NFS. Still bad. Used COPY and DIFF to capture some bad data and then examined it. Observed a pattern of 15 or 16 bytes being copied over another group of 15 or 16 bytes at a location 64 bytes later in the file. (If you've been there before, this probably tells you the answer. It didn't tell me, yet.) I swapped ethernet cards. The problem went away. (I hadn't swapped them before because I didn't want to bother updating the ethers files.) Analysis: PC-NFS (like all sun NFSs) is implemented over UDP, but with UDP checksumming turned off. (^%$&@^#!$% !!!) If an ethernet packet gets clobbered, the error may therefore not be detected by NFS, since it isn't checksumming. I can't find my reference, but I believe I've heard that this particular failure mode is one present in early revs of the DS8390 ethernet chip. (I sure hope my memory is right; if not, I'm unfairly maligning National. They did have a number of glitches and I THINK this is one of them.) We have been having some broadcast storms lately, increasing the odds of this failure and causing the recent increase in symptoms. The new card has a newer rev DS8390 (8824 versus 8742C4 date code). I should have recognized the failure mode earlier. I wrote the WD8003E and 3C503 drivers in the Clarkson collection (though they're not what I was using with PC-NFS, of course) so I should have known. My questions (which I should get purchasing to check, but as long as I have the floor): 1) Anyone know where I can get a new date code DS8390 in quantity one? 2) Any idea if Western Digital will upgrade this WD8003E after it's out of warranty? (It's not their fault, of course.) Bob Clements, K1BC, clements@bbn.com