Date: Sun, 15 Jul 2001 02:37:41 -0400 From: Bob Johnson <bobj@ufl.edu> To: Ben Lovett <blovett@bsdguru.com> Cc: mobile@FreeBSD.ORG Subject: Re: Disk clicking... (Was: Re: Dell Inspiron 8000 and suspend-to-disk) Message-ID: <3B513A35.F0F32B9B@ufl.edu> References: <20010703101035.A1027@bsdguru.com> <3B433888.7020304@quack.kfu.com> <3B4353BE.927522EF@ufl.edu> <20010704210528.A691@bsdguru.com> <20010707045013.A1368@sydney.worldwide.lemis.com> <20010714125947.A7983@bsdguru.com>
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Ben Lovett wrote:
>
> I believe I saw Greg Lehey (grog@FreeBSD.ORG) write this:
> > On Wednesday, 4 July 2001 at 21:05:28 -0700, Ben Lovett wrote:
> > > I believe I saw Bob Johnson (bobj@ufl.edu) write this:
> > >> Nick Sayer wrote:
> > >>> Ben Lovett wrote:
> > >>
[...]
> > > I believe this is the reason behind some strange noises that I hear
> > > comming from my disk every once in a while. It sounds like one of
> > > the heads is moving rather abruptly, or something like that.
> >
> > Well, the heads all move together.
> ok..
> >
> > > Has anyone else noticed similar behaviour on Dell i8k's built as of
> > > late?
> >
> > A lot of us noticed "clunk" noises from the disks of 7500s built
> > between 12 and 18 months ago. I had mine replaced as a result, and
> > the new disk has never made any noise. Mike Smith didn't have his
> > replaced, and the disk still goes "clunk" after 18 months, but he
> > doesn't have any other problems with it.
>
My 7500 makes what you might call "clicks" or "clunks" when it does
what sound to me like long seeks. I've heard it from so many drives
that I consider it normal. My mother-in-law's laptop had a horribly
noisy and slow drive that she thought was failing -- it was merely a
highly fragmented Windows swap file. Cleaned that up and the system
got quiet and fast again (isn't that neat? Windows is actually
designed to get slower with use!).
When doing most disk-intensive operations on this 7500 (e.g. deleting
/usr/obj) it is very quiet, but during normal operation it clicks
and clunks once in a while. I've always assumed that was a long seek
related to flushing a buffer or something. Long seeks tend to be
(in my experience) relatively noisy on many drives.
> Well.. I guess that I am observing this behavior on my replacement disk,
> I'll live with it. Unless I hear different.
>
> On a sort of side note.. I was discussing this issue with my boss
> yesterday, and he was explaining to me that when hard drives are
> manufactured, because of the nature of the mass-production, the platters
> will never turn out without flaws, and thus will have some bad sectors.
> So, when the drives go through their low-level formatting at the
> factory, those sectors will be marked as "bad" on some part of the
> drive. He was telling me that the reason that the drive may be clicking
> is that the heads are comming across one of these sectors that is marked
> bad, when it thought there was data there (or something to that effect),
> and then resyncing itself. Does that make sense? I believe that is
> what he was saying.
A sector mapped bad shouldn't be accessed in the first place, but
it sort of makes sense. My understanding is that when a SCSI drive
(and probably recent IDE drives) detects errors in a sector, it maps
out that sector and replaces it with one from a spare sector pool at
the end of the disk. Thus, when that sector is accessed, there is a
seek to the end of the disk which you might hear. I assume that
sectors mapped bad at the factory are replaced by the next available
sector, so there would be no seek involved. Thus, only newly bad sectors
would cause noise.
>
> Thanks again..
>
> -ben
> --
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> Ben Lovett printf("Hello world!);
> blovett@bsdguru.com return 0;
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> If Bill Gates had a dime for every time a Windows box crashed...
> ...Oh, wait a minute, he already does.
>
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