Date: Thu, 26 Apr 2001 09:33:07 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: Riccardo.Veraldi@fi.infn.it Cc: <freebsd-alpha@FreeBSD.ORG> Subject: Re: MACHINE CHECK with dd Message-ID: <15080.9107.734821.462496@grasshopper.cs.duke.edu> In-Reply-To: <Pine.NEB.4.33.0104261514080.12981-100000@nikita.fi.infn.it> References: <Pine.NEB.4.33.0104261514080.12981-100000@nikita.fi.infn.it>
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Riccardo.Veraldi@fi.infn.it writes: > > dd bs=145600000 if=pp of=pp2 > > pp is a file of 145600000 bytes. > this is a working repeatable example. > if I issue it the machine crashes every time (machine check error). > Any ideas ??? Yes. The same idea I had when you complained about machine checks before -- you've got flaky hardware. When you use such a large blocksize, you're causing dd to grow _VERY_ large (roughly 140MB). This stresses the memory system, as well as the I/O system. If you have less that 150MB or so of ram, you're going to start paging heavily as well. This is the sort of scenario where if you've got hardware problems with a machine, you're going to see them. Also bear in mind that the apecs was the first workstation class alpha pci chipset that DEC ever did, and may not be as solid as their later producsts. It certainly doesn't perform as well (see ftp://ftp.digital.com/pub/DEC/SRC/publications/shand/fccm97.pdf) We had a few AS400s (basically the same thing as your AS255) that would crash every few months with a machine check error when running Tru64. So, in conclusion, either don't push it so hard, or replace the failing hardware. Drew ------------------------------------------------------------------------------ Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin Duke University Email: gallatin@cs.duke.edu Department of Computer Science Phone: (919) 660-6590 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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