I have read through some of the Hitachi documents for my hard disk, and
came across this, in the Hard Disk Drive Specification (available
on-line as TS5K500.B_OEMSpec_r12a.pdf). Does this provide any useful
information?
6.3.6 Load/unload
The product supports a minimum of 600,000 normal load/unloads.
Load/unload is a functional mechanism of the hard disk drive. It is
controlled by the drive micro code. Specifically, unloading of the heads
is invoked by the following commands:
Standby
Standby immediate
Sleep
Load/unload is also invoked as one of the idle modes of the drive. The
specified start/stop life of the product assumes that load/unload is
operated normally, not in emergency mode.
6.3.6.1 Emergency unload
When hard disk drive power is interrupted while the heads are still
loaded the micro code cannot operate and the normal 5-volt power is
unavailable to unload the heads. In this case, normal unload is not
possible. The heads are unloaded by routing the back EMF of the spinning
motor to the voice coil. The actuator velocity is greater than the
normal case and the unload process is inherently less controllable
without a normal seek current profile. Emergency unload is intended to
be invoked in rare situations. Because this operation is inherently
uncontrolled, it is more mechanically stressful than a normal unload.
The drive supports a minimum of 20,000 emergency unloads.
6.3.6.2 Required Power-Off Sequence
The required host system sequence for removing power from the drive is
as follows:
Step 1: Issue one of the following commands.
Standby
Standby immediate
Sleep
Note: Do not use the Flush Cache command for the power off sequence
because this command does not invoke Unload.
Step 2: Wait until the Command Complete status is returned. In a typical
case 500 ms are required for the command to finish completion; however,
the host system time out value needs to be 30 seconds considering error
recovery time.
Step 3: Terminate power to HDD.
This power-down sequence should be followed for entry into any system
power-down state, system suspend state, or system hibernation state. In
a robustly designed system, emergency unload is limited to rare
scenarios, such as battery removal during operation.
Steve
On 11-09-04 01:47 PM, Tomas Bodzar wrote:
after reading that fbsd thread it seems that it's problem of shitty hw
where acer can be count for sure. I saw a lot of them with fine
numbers in specs, but together it was worse then some older laptop
from ibm or similar vendor. Slow buses, cheap hw, missing specs and so
on. In the end expensive slow toy
On 9/4/11, Benny Lofgren<bl-li...@lofgren.biz> wrote:
On 2011-09-04 07.39, David Vasek wrote:
No, Marco, it is not true. There is a difference between unloading the
heads in a controlled way and by an emergency retract. Doing emergency
retract repeatedly is not good, really.
That used to be true in the dark ages, when disk drives were as large as
washing machines and the actual disk packs were removable and 14" in
diameter. But in this day and age, what Marco says is entirely correct.
The OP can safely ignore this from a disk durability standpoint, although
it may of course be a nuisance that the disk doesn't power down when
shutting down OpenBSD (if that's indeed what happens, I'm not sure I fully
understood the description).
Also, "emergency retract" is a misnomer, the SMART attribute in quesetion
is actually called "Power-off Retract Count". Only Fujitsu (to my
knowledge) for some reason calles it Emergency Retract Cycle Count. In any
case it's a bullshit value to base any reliability predictions on, unless
maybe, MAYBE if it runs into the tens or hundreds of thousands.
Regards,
/Benny
On Sat, 3 Sep 2011, Marco Peereboom wrote:
Removing power from a running drive won't do anything to it. Just use
OpenBSD
and stop looking at worthless diagnostics tools.
On Sep 3, 2011, at 15:41, Steve<scha...@aei.ca> wrote:
Hi all,
I've got a strange situation with OpenBSD 4.9 on a new laptop, an Acer
Aspire 1430 with an Hitachi 500 GB SATA disk, model HTS545050B9A300. When
shutting down, OpenBSD does not spin down the disk, resulting in an
"emergency
unload" according to Smart terminology. Until I can resolve this
issue, I've
uninstalled OpenBSD from it, since smartctl reports in Slackware that
there
have been 17 "Power-off Retract" events so far, which could damage the
disk in
the long run. However I would really love to run OpenBSD on my laptop
for the
simple reason that I love it so much more than Linux.
Can anyone suggest what I could do to stop this from happening? I
found a
discussion on a FreeBSD mailing list identifying and trying to resolve
the
exact same thing through kernel recompilations:
http://freebsd.1045724.n5.nabble.com/Re-Spin-down-HDD-after-disk-sync-or-befo
re-power-off-td4043068.html
However, neither using FreeBSD nor patching the OpenBSD kernel would
be a
preferred choice for me. I'm sure there must be a simpler solution,
maybe a
sysctl setting I'm over-looking...? I've tried both IDE and AHCI modes
in the
BIOS with the same results.
Thanks,
Steve Schaller
--
internetlabbet.se / work: +46 8 551 124 80 / "Words must
Benny Lofgren / mobile: +46 70 718 11 90 / be weighed,
/ fax: +46 8 551 124 89 / not counted."
/ email: benny -at- internetlabbet.se
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