Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!rutgers!ucla-cs!cit-vax!mangler From: mangler@cit-vax.Caltech.Edu (System Mangler) Newsgroups: comp.unix.wizards Subject: Re: SI 9900 hangs Message-ID: <3321@cit-vax.Caltech.Edu> Date: Fri, 24-Jul-87 06:00:44 EDT Article-I.D.: cit-vax.3321 Posted: Fri Jul 24 06:00:44 1987 Date-Received: Sat, 25-Jul-87 12:51:19 EDT References: <8269@brl-adm.ARPA> Organization: California Institute of Technology Lines: 32 Summary: common problem, check the power supply In article <8269@brl-adm.ARPA>, eichelbe@nadc.arpa (J. Eichelberger) writes: > Every so often we get a system hang. All activity on the SI controller > stops. Hitting the reset on the toggle switch restarts everything. Most > of the time we don't see any error messages. If we do see one, it's > hp0: not ready We get these too. The last time it happened, I checked the registers, and all 5 drives had just completed a seek (a sign that the massbus datapath is marked "busy") and they all had the UNS (unsafe) bit set. cithex.caltech.edu has the same problem. They run VMS. The SI local office says this is a common problem, typically caused by marginal power supply output. I've not had the chance to verify this (there isn't enough downtime on this machine for my purposes). > We are using the standard 4.3 BSD hp.c for the driver. I sure hope that you're using error-free packs. The error position determination algorithm in that driver depends on separate counters for the number of bytes DMA'd and the number of bytes read/written; but the SI 9900 uses the first counter for both, so on an error, the driver thinks that more sectors were written than actually were. (Before you start flaming about SI: that problem is easy to work around compared to some of the bugs I've seen in the Emulex SC7000). Seismo has a version of hp.c that works around this by looking at the track/sector register (HPDA) instead. It can still lose data silently, but if retries are a rare event, it can be lived with. Don Speck speck@vlsi.caltech.edu {ll-xn,rutgers,amdahl}!cit-vax!speck