hard disk behavior

[jb]

Erich Dollansky <erichfreebsdlist <at> ovitrap.com> writes:

> ... 
> I have no idea what causes the noise. What is the machine doing when you hear
> it?
> 
> Erich
> 

I use it as a desktop.
Mostly web browsing, Firefox, there is always some background activity in
there, like financial data streaming, etc.
But this sound is so concerning: click ...click-clack, click-clack ... etc.

$ top
last pid: 62014;  load averages:  0.09,  0.06,  0.06    up 4+02:07:06  18:56:08
63 processes:  1 running, 62 sleeping
CPU 0:  0.8% user,  0.0% nice,  2.0% system,  0.0% interrupt, 97.2% idle
CPU 1:  3.1% user,  0.0% nice,  0.8% system,  0.0% interrupt, 96.1% idle
Mem: 190M Active, 890M Inact, 261M Wired, 312K Cache, 112M Buf, 644M Free
Swap: 3043M Total, 3043M Free

  PID USERNAME    THR PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
58910 jb           22  20    0   319M   262M uwait   0  14:07  1.07% firefox-bi
 1283 root          1  20    0  9716K  1148K select  1   5:15  0.98% moused
 3344 root          2  23    0 14156K  4940K select  0   8:31  0.00% upowerd
 1865 root          1  20    0  9612K  1104K select  1   7:17  0.00% powerd
 1978 haldaemon     2  20    0 23300K  6292K piperd  0   7:07  0.00% hald
58961 jb            1  20    0   118M 30068K select  0   5:08  0.00% npviewer.b
58845 jb            1  20    0   374M   309M select  1   4:37  0.00% Xorg
58951 jb            2  20    0 70360K 31416K kqread  0   2:10  0.00% plugin-con
 1757 messagebus    1  20    0  9812K  2520K select  0   1:46  0.00% dbus-daemo
59121 jb            5  22    0 56108K 29028K uwait   1   0:32  0.00% pan
 1902 root          1  20    0 11324K  3360K select  1   0:23  0.00% sendmail
58882 jb            1  20    0 11944K  2904K select  0   0:22  0.00% gam_server
59173 jb            2  20    0 40164K 20444K piperd  1   0:15  0.00% Terminal
58883 jb            2  20    0 40168K 19744K piperd  1   0:09  0.00% xfce4-pane
58884 jb            1  20    0 39932K 20396K select  0   0:07  0.00% xfdesktop
[jb at localhost ~]$