Re: [9fans] file server page faulting

[nigel@9fs.org]

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It really ought not to page fault for a bad block. The file server
driver certainly recovers from bad block accesses, as I saw
quite a few on my server this summer. Unfortunately, as my
fake worm filled up, I have pulled the scsi drives from the server,
replacing them with IDE as the prices make it prohibitive to
work any other way. 70Gb SCSI drives are £450 +VAT here,
whereas 80GB IDE are <£80 +VAT. You can mirror the drives
and still spend less than half for the same capacity.

I still have SCSI in my terminal.

However, there are compatibility problems between 53c8xx
chips and PCI busses, which is nothing to do with Plan 9. I
certainly found that old controllers (53c810s) did not
work reliabuly in PCI 2.1 busses; bus faults I think. I guess
that the same issues could exist with a new controller and
an old motherboard, but I don't have any old motherboards
any more.

It is certainly supported hardware, but only if the hardware
is plugged into a compatible socket.

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From: Andrew <afrayedknot@thefrayedknot.armory.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] file server page faulting
Date: Fri, 13 Sep 2002 08:23:48 -0700
Message-ID: <20020913152348.GA19419@thefrayedknot.armory.com>

On Fri, Sep 13, 2002 at 04:14:04PM +0100, nigel@9fs.org wrote:
> > the hardware is an older pentium (90?) it has 40 mb of ram with integrated
> > s3 video and uses a symbios scsi adapter with a 2.5gb hard drive. No
> > dump media is attached. The ethernet card is a i82557 mini-nic. I can
> > make this happen by usually accessing lots and lotsof data. For example
> > if i cat /dev/zero into a file then cat it back out a couple of times
> > it usually breaks. I swapped the scsi setup into another system (my
> > terminal actually), which does not have an integrated video controller
> > and the same type of nic. It had the same problem. The crash is known
> > to happen seemingly sporadically also.
> >
> > is it worth reinstalling onto ide drives? I can backup all my changes
> > fairly easily.
>
> It may be. When it breaks, what is the address it happens at?
> When you say integrated S3 do you mean in the chip set? Does it used
> shared memory?
i will try and get the address.
>
> The possible issues here are
>
> 1. the S3 is sharing the memory; there is no allowance for this, and
>     when the buffer cache meets the frame buffer horrible things happen

the reason i doubt this is that i get the same results on a different
machine that does not have an integrated controller, it has an isa video
card of trident genre so i doubt that the memory is shared between those two.

>
> 2. which symbios controller? check that the PCI bus specs. match, as
>     older symbios controllers don't work on newer PCI busses
it is a fairly new, working, symbios controller I am 99% certain it is
the one specified in the supported hardware section. i will check when
i get home from work. but i believe its listed as scsi0=type=ncr53c8xx
in the plan9.ini file.
>
> If it is the scsi controller, and the bus specs. match, then I get more
> interested, having written the symbios driver.
>
Im planning on putting the scsi setup in one of my linux machines and
seeing what happens if i cat the whole drive out. That way if theres
any blocks that its having trouble with i can find out.

thanks for your help.