[ltp] HDAPS and drives that can't park & can you park 2 drives (main+ultraybay)?

[Marc MERLIN]

On Fri, Dec 28, 2007 at 12:37:47AM -0200, Henrique de Moraes Holschuh wrote:
> > Just curious about this: does it mean that all drives support some kind
> > of head parking, but that the command is different, and the current
> > kernel doesn't know what the right unload command for each drive is?
> 
> No, some drivers have UNLOAD IMMEDIATE support, while others don't. And many
> which do don't announce it properly (especially if it is a firmware
> patch...)
 
Gotcha, thanks.

> *If* it is a drive that Lenovo ships (i.e. same model *and* firmware
> family), you may luck out and find that you can coax the Lenovo firmware to
> install into it.  Look at the foruns at thinkpads.com (I think).
> Otherwise, get a drive which does APS by itself (there are some, sorry I
> don't know which ones, but I believe the latest Seagate ones do so. Ask
> around), or try to replace it with a drive known to support UNLOAD
> IMMEDIATE...
 
Good to know, thanks.

On Thu, Dec 27, 2007 at 11:38:13PM -0500, Theodore Tso wrote:
> The Seagate Momentus 7200.1 and 7200.2 drives both support APS as well
> as UNLOAD IMMEDIATE --- and I believe some Lenovo driver are in fact
> using Segate Momentus disks.
 
I'm mostly interested in bigger drives though. For instance, I'm very
interested in getting the upcoming fujitsu 300GB drive:
http://www.laptopical.com/mhx2300bt-drive.html

That said, if someone knows of a good 250GB drive available now, and
that can do unload, I might be interested :)

> It actually makes a huge amount of sense to do APS in the drive,
> because it means you don't have to constantly wake up the CPU to
> sample the accelerometers to see if the laptop is falling.  So it
> makes a huge difference in terms of batter life and power saving.

That sounds great. Looking forward to seeing this in my laptop soon :)

> (The recent hdaps patch stops polling the accelerometer if the daemon
> isn't running, to save power, but if you want to protect your hard
> drive, the daemon has to be running, and there goes the power savings.
> If you use a hard drive that has the accelerometers built in, and can
> sample them in hardware without needing to wake up the main CPU, so
> much the better.)

I read your power saving page, but I'm afraid, my Z61p does quite poorly
right now, I typically get 25W, and sometimes down to 20W when I'm lucky
(it's very non deterministic). That's after fglrx powersave, laptop mode
and others, otherwise I was at 30W-ish.

I'll post a separate message about this to see if I can gather more
ideas.

Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems & security ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/