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SubjectRe: [LINUX-KERNEL] HDD Noise stopped with cat /dev/zero
On Oct 17, 11:51pm, David Monro wrote:
> Subject: Re: [LINUX-KERNEL] HDD Noise stopped with cat /dev/zero
> Dunno - but I have an old machine where I can here noises from the ancient
hard
> drive (we are talking 8 year old 40Mb MFM here) when network traffic is going
> through the machine - go figure. (And no, it isn't the drive doing things -
> the disk select light (remember those?) isn't even on). If I have the sound
> card plugged in I get to listen to the traffic quite loudly too :-(
>
> I've also had at least two machines which made strange noises when the case
was
> open and in quiet surroundings with no sound card or anything - again network
> traffic was triggering the noises, though I have no idea why I could hear it.
> I can remember one particularly strange incident where I could here noises
> when I was running a CPU intensive job (raytracing) as opposed to the machine
> being idle. I can only guess I am hearing subharmonics of the bus traffic but
> I find that hard to believe.
>
> Just one of those things I guess.

It's not all that unbelievable. Several common electrical devices are
microphonic. Traditionally, that means that vibration (sound, shock, etc.) can
effect the electrical properties of the devices. IMHO, it also implies that
changes in the voltages or currents within the device may have the reverse
effect of causing vibration. Transformers display this property and they are
present in every NIC and in most every sound card. Hard drives, well, those
are blatantly microphonic. As a previous poster on this thread has already
mentioned, hard drives can be effected by power supplies that are at the edge
of their specs or are simply out of spec.

Everything is possible, some things are just more likely than others.

Cheers,
David

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