My SAMSUNG HM251JJ also suffers this problem. If hdparm sets -B128, it sticks:
sudo hdparm -B128 /dev/sda /dev/sda: setting Advanced Power Management level to 0x80 (128) APM_level = 128 And as per the hdparm manpage, it does not spin down. Ever. But if it sets -B127, the hard disk assumes a value of 1: sudo hdparm -B127 /dev/sda /dev/sda: setting Advanced Power Management level to 0x7f (127) APM_level = 1 And it starts to spin down a lot more than it should, sometimes even during disk reads! hdparm -i shows: /dev/sda: Model=SAMSUNG HM251JJ, FwRev=2AA00_00, SerialNo=xxxx Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs } RawCHS=16383/16/63, TrkSize=34902, SectSize=554, ECCbytes=4 BuffType=DualPortCache, BuffSize=16384kB, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=488397168 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4 DMA modes: mdma0 mdma1 mdma2 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 AdvancedPM=yes: disabled (255) WriteCache=enabled Drive conforms to: ATA/ATAPI-7 T13 1532D revision 0: ATA/ATAPI-1,2,3,4,5,6,7 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/913050 Title: Explicit APM values in hdparm-functions cause Load Cycle Count hell To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/hdparm/+bug/913050/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs