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From: kenb@amc-gw.amc.com (Ken Birdwell)
Newsgroups: comp.sys.next
Subject: Re: memory (was: slab vs. cube and $$)
Message-ID: <4326@amc-gw.amc.com>
Date: 1 Dec 90 06:55:48 GMT
References: <12081@life.ai.mit.edu> <1990Nov29.161041.15775@magnus.ircc.ohio-state.edu> <1990Nov30.013031.25032@mp.cs.niu.edu> <12108@life.ai.mit.edu>
Reply-To: kenb@roke.amc.com (Ken Birdwell)
Organization: Applied Microsystems, Redmond, WA
Lines: 28


>caroma@wheat-chex.ai.mit.edu (Carl R. Manning) writes:
>
>I realize that the NeXT can have parity memory; my original question
>remains unanswered: What does the NeXT do when it gets a memory parity
>error?  (e.g. Does it lock up the machine immediately?  Or does it report
>the error and allow you to decide whether to try continuing?  If the
>error is in memory which isn't critical to what I'm doing, I'd rather
>not lose all my work with a crashed machine -- at least give me the
>chance to try to save what work I can.)

>[stuff about cosmic rays causing parity errors and EEC and stuff]


I suppose that the process that got the parity error could get a SIGBUS 
error.  I'm sorry but it's really dangerous to keep running after that sort 
of thing happens.  On most UNIX system you'll get a 'panic: parity error' 
with no idea of where and the system will shut itself off.  Now this is alot 
better then doing stuff like, spewing to a now random file handle or jumping 
into a function that formats your hard disk or at a minimun trashes all your 
saved data because some comparison failed or whatever but I agree, powering 
down is nasty.  I think that killing the process (if possible; if parity 
error occured in the schedular, youre screwed) is a resonable thing to do.  
Its kinds nice to not let your program go into Lala-land without telling you.  
Just think of it as a random SEGV, and I know of no-one who thinks it's 
resonable to continue after one of those (except for Mac and DOS people :^).

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