Re: IBM HDAPS things are looking up

Alejandro Bonilla
2005-07-04T18:27:58Z

Jens Axboe wrote:

>
>That's madness, we can't add a kernel thread for every single little
>silly thing. You don't need to stop any io, you just want to make sure
>that your park request gets issued right after the current io has
>finished.
>
>
HI,

For me, the heads have to park so fast. That I would be afraid of a
kernel panil or something that could happen if you park the head so fast
that it won't even tell the kernel it did, or because ext3 couldn't
update or any crazy reason.

I use a lot a project called laptop_mode, which suspend the hd until
you do a request to the kernel or the HD and it spins up the HD. I think
somehow, the kernel is not fast enough to do what we want, I mean, I
don't see it.

Imagine you are in starbucks, your laptop is over a 1.2 M table,
Linus just said that a new kernel is out. So you simply download it, and
now you are compiling it. But, you invited your kid to Starbucks. And
while your CPU is at 100% and full throttle HD usage. Then your kid
trips on the cable or simply pushes the PC out.

Do you think that the kernel will STOP, HOLD and park the head in
less than a second? OR on the time we need?

I would say is a dammed good kernel if it would. (could RTOS, make
things faster)

Simply send the flames my way if you think I'm totally wrong. Which I
might be. I really don't know...

.Alejandro