Re: IBM HDAPS things are looking up (was: Re: [Hdaps-devel] Re: [ltp] IBM HDAPS Someone interested? (Accelerometer))

From: Pavel Machek (pavel_at_suse.cz)
Date: 07/04/05

  • Next message: Lenz Grimmer: "Re: IBM HDAPS things are looking up" 
    Date:	Mon, 4 Jul 2005 15:03:37 +0200
To: Jens Axboe <axboe@suse.de>

    Hi!

    > > > > This is exactly what I said. Use hdparm to make the HD park
    > > > > inmediatelly. I did send the email to the HDPARM developer, but he never
    > > > > replied. I asked him what would be the best way to make the HD park with
    > > > > no exception and then let it come back 5 or 10 seconds later.
    > > >
    > > > IIRC, you don't have to do anything to wake up the drive after a
    > > > STANDBYNOW command, if you want to be on the safe side you just issue an
    > > > IDLEIMMEDIATE. So your code will look something like:
    > >
    > > the problem for this will be that this app will also want to prevent ANY
    > > io going to the disk for a few seconds.
    > >
    > > I mean, what use is parking the head if you notice the laptop falling,
    > > when the kernel submits IO to it and wakes it up again before it hits
    > > the ground :)
    >
    > Yeah, that likely needs a little help from the ide driver. If you force
    > a spindown, you will effectively have parked the head for as long as the
    > spindown + spinup takes. That could turn out to be enough, it will take
    > more than 1-2 seconds anyways.

    Actually, "spin disk down and keep it down" would be nice for other
    reasons. Taking computer for a jog playing mp3s from ramdisk is
    something I'd like to do...
                                    Pavel 

    -- 
64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms         
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
  • Next message: Lenz Grimmer: "Re: IBM HDAPS things are looking up"

    Relevant Pages