Re: AW: DOC vs. IDE

[Christopher Bergeron]

That actually sounds like a brilliant idea.  I wonder if anyone on the 
list can confirm performance... does the CFcard appear as a standard IDE 
disk or is there a driver or anything necessary?

-CB

Baab, Ingo wrote:
> Hello Christopher,
> mounting a CF-2-IDE-Adapter /w CF-Card would be 
> a little bit faster than the rotating thing, or?
> --ingo
>
> -----Ursprüngliche Nachricht-----
> Von: Christopher Bergeron [mailto:[e-mail]]
> Gesendet: Mittwoch, 23. Oktober 2002 17:23
> An: [e-mail]
> Betreff: Re: DOC vs. IDE
>
> you can't fit X onto the DoC you can buy today.
>
> Fasted boot I've seen is with the kernel in DoC, then mount /dev/hda1 as
> /.
>
> ron
>
> Even an X like Qt embedded?  My Zaurus only has 32Mb on it, and it boots
> into X in about 4 seconds.  While I don't expect _that_ speedy of a boot, I
> would think I could achieve significantly less than 35(ish) seconds it takes
> now.  Also, did you factor in the IDE spinup boot delay of having an IDE  /.
> directory?  If the DOC+IDE is faster, do you mean throughput wise or time
> wise?  I'm referring to an earlier message that you replied to Todd Johnson
> and his boot times (message below).  It seemed as if the 2 emails conflict
> in what they're saying, so I just wanted to ask for a little clarification
> (not doubting you, just a little unclear on the principle).
>
> Essentially what I'm wondering is if a small footprint X could be booted
> into via DOC and if it would be faster than DOC+IDE (considering the IDE
> spinup delay).
>
> Your thoughts?
>
> Ronald G Minnich wrote:
>
> On Sun, 29 Sep 2002, Christopher Bergeron wrote:
>
> Can anyone give me advice on what will acheive the fastest boot time?
> My options are the LinuxBIOS coupled with a DOC root or with root
> configured on hda1 (IDE).  I boot into X and I'll need standard
> modules loaded.  I'd like to fit the entire install on a DOC but only
> IF I'll get a faster load/boot.
>
> you can't fit X onto the DoC you can buy today.
>
> Fasted boot I've seen is with the kernel in DoC, then mount /dev/hda1 as
> /.
>
> ron
>
> On Fri, 4 Oct 2002, Todd E. Johnson wrote:
>
> BTW, it seems that there is no booting action (Based on the Serial
> > output) until the HDD spins up.  Is this a result of me keeping my root
> > file system on the HDD?
>
> you can't do anything until the HDD spins up, and yes it's because you've
> god file system on the HDD. There's not much to be done for this.
>
> ron

AW: DOC vs. IDE

[Steve M. Gehlbach]

> That actually sounds like a brilliant idea.  I wonder if anyone on the

list can
> confirm performance... does the CFcard appear as a standard IDE disk or is

there
> a driver or anything necessary?
> -CB

Same as IDE, just a mechanical issue to convert the wiring to IDE connector
and add power.  There are a number available, here's one:
http://www.pcengines.com/cflash.htm.

The current code (maybe changed recently don't know) uses a rough time delay
for spin up that needs to be tinkered with.

Boots pretty quickly with CF, but, as Linux boots, "Calibrating CPU..."
takes a lot of time (several seconds).  Anyone know if this is necessary?

-Steve

AW: DOC vs. IDE

[Ronald G Minnich]

On Wed, 23 Oct 2002, Christopher Bergeron wrote:
> That actually sounds like a brilliant idea.  I wonder if anyone on the
> list can confirm performance... does the CFcard appear as a standard IDE
> disk or is there a driver or anything necessary?

we're doing it here on the PCM-5823-A2 geode cards. We use CF as /dev/hdc,
there is no /dev/hd1. Works fine.

ron

AW: DOC vs. IDE

[Richard A. Smith]

On Wed, 23 Oct 2002 14:28:23 -0600 (MDT), Ronald G Minnich wrote:
> On Wed, 23 Oct 2002, Christopher Bergeron wrote:
> > That actually sounds like a brilliant idea.  I wonder if anyone on the
> > list can confirm performance... does the CFcard appear as a standard IDE
> > disk or is there a driver or anything necessary?
>
> we're doing it here on the PCM-5823-A2 geode cards. We use CF as /dev/hdc,
> there is no /dev/hd1. Works fine.

I'll pipe in a little bit of personal experience here.  If you are
_just_ using a CF with an IDE adapter then all is well and things
will work great.

During bringup and debug though its nice to have a big HD with a full
linux distribution on on it so you can develope on your target.

However if you are using a CF _and_ a normal IDE drive you may run
into a gotcha.  In the 2.2 linux IDE code there are clauses that if a
CF device is dectected on hda it will NOT probe for hdb.  Same goes
for hdc and hdd.  There is no output telling you its skipping it
either.  Apparently there were some early CF devices that did some
funky stuff with the diag signal (drive dection) and Andre (the 2.2
IDE maintainer) chose to blacklist all CF devices.

The fix is to feed the kernel some parameter like ide0=flash or
something similar to make it go ahead and probe.

I haven't looked at the 2.4.x IDE code so I don't know if it carried
over or not.

But if you mysteriously don't have an hdb with a CF hooked up in your
system go check the IDE probing code before you pull you hair out
trying to figure out whats wrong with your hardware like I did.