changing iMac hard drive

[Pyx Findlekind]

>Date: Sat, 15 Mar 2003 12:47:15 -0800
>Subject: [HM] Re: changing iMac hard drive
>From: T. Brown / groucho <btgroucho at earthlink.net>
>
>On Saturday, March 15, 2003, at 09:28  AM, Pyx Findlekind wrote:
>
>>  Question: Which generates the most heat - HD or CPU?
>>  Also: I'm noticing an increase in HD noise level recently when the
>>  iMac is inactive (hum/buzz). Is this something to be concerned about?
>  > Am I just imagining this?
>  >

...

>As far as making noise while not in use it sounds as though your
>computer is indexing either from Sherlock of Norton FileSaver.
>
>You can run PeekaBoo ( shareware ) to see what is going on while it is
>" idle "
>
>groucho

I am not referring to the clicking ticking tap-dancing sound as the 
HD accesses or writes, but of a constant buzzing/humming sound which 
seems louder at some times than at others. When I spin down the drive 
through the Energy Saver Control Panel the sound ceases.
As an experiment I left the iMac on all night with the drive spun 
down; next morning the iMac is radiating as much heat as it usually 
does, so, I assume that most of the heat is generated by the CPU.