https://launchpad.net/bug59695.html
...When switching to battery power, /etc/acpi/power.sh issues the command hdparm -B 1 to all block devices. This leads to extremely frequent load cycles. For example, my new thinkpad has already done well over 7000 load cycles -- in only 100 hours. That's at least one unloading per minute. Googling for "load unload cycles notebook OR laptop" shows that most laptop drives handle up to 600,000 such cycles. As these values clearly show, this issue is of high importance and should be fixed sooner rather than later.
Please see for yourself how often your drive is load cycling:
smartctl -d ata -a /dev/sda
(This command is for an SATA drive; you'll need to install the smartmontools package first.)
See also http://paul.luon.net/journal/hacking/BrokenHDDs.html for a rather dramatic account of the effects the current default values may have.
Just in case the load/unload timeout depends on the specific laptop or disk model, here are my system specifications:
ThinkPad Z60m & Hitachi HTS541080G9SA00 disk (80GB)...
laptop axioo gw sendiri baru, baru sekitar 3 bulan kurang diinstal ubuntu, sebelumnya 2 bulanan diinstal debian.
pas dicek dengan "smartctl -d ata -a /dev/sda", load cyclenya udah 57000 (dah ampir 10% dari 600k, limit rata2x menurut artikel di atas). padahal baru 5 bulan dan jarang dipake. pas gw amatin, dalam beberapa detik (5 detik) udah nambah 1, nambah 1, ...
trus gw ketik perintah "hdparm -B 255 /dev/sda", jadi berenti counternya, setelah diamati 10-15 menit juga tetap belum naik2x.
dan memang setelah diinstal ubuntu muncul bunyi seperti detak jantung (click). dan sekarang setelah diissue perintah di atas jadi berhenti!
