My laptop hard drive started clicking all the time, driving me crazy.
Thanks to Vorlon and the other people on #debian-women I've been able to
finally get to this
page and this
commandline:
hdparm -B 254 /dev/hda
The noise has finally stopeed and I'm in harmony with my laptop once again.
Note: the culprit for setting the original value of -B seems to be laptop-mode,
specifically in /etc/laptop-mode/laptop-mode.conf, the default values of
LM_AC_HD_POWERMGMT and NOLM_AC_HD_POWERMGMT.