Patches for ppc?

Patches for ppc?

[Johan Borkhuis]

Hello,

I am working with a PPC-kernel, and came across a problem with the PCI 
initialisation. On this mailing list I see a lot of patches, but they 
are all for the PowerPC architecture. Are patches for the PPC 
architecture still processed?

I know that the ppc-architecture is being phased out, but for the moment 
I am stuck with it, as the board I am working with is not supported in 
the powerpc architecture.

Kind regards,
    Johan Borkhuis

Re: Patches for ppc?

[Kumar Gala]

On Aug 17, 2007, at 2:43 AM, Johan Borkhuis wrote:

> Hello,
>
> I am working with a PPC-kernel, and came across a problem with the PCI
> initialisation. On this mailing list I see a lot of patches, but they
> are all for the PowerPC architecture. Are patches for the PPC
> architecture still processed?
>
> I know that the ppc-architecture is being phased out, but for the  
> moment
> I am stuck with it, as the board I am working with is not supported in
> the powerpc architecture.

If it fixes a bug we'll take patches to arch/ppc.

- k

Re: Patches for ppc?

[David Woodhouse]

On Fri, 2007-08-17 at 09:43 +0200, Johan Borkhuis wrote:
> I am working with a PPC-kernel, and came across a problem with the PCI 
> initialisation. On this mailing list I see a lot of patches, but they 
> are all for the PowerPC architecture. Are patches for the PPC 
> architecture still processed?
> 
> I know that the ppc-architecture is being phased out, but for the moment 
> I am stuck with it, as the board I am working with is not supported in 
> the powerpc architecture. 

If you've having to submit or look for patches, it sounds like it isn't
working with the obsolete arch/ppc either. Time to update, perhaps?

-- 
dwmw2

Re: Patches for ppc?

[Johan Borkhuis]

David Woodhouse wrote:
> On Fri, 2007-08-17 at 09:43 +0200, Johan Borkhuis wrote:
>   
>> I am working with a PPC-kernel, and came across a problem with the PCI 
>> initialisation. On this mailing list I see a lot of patches, but they 
>> are all for the PowerPC architecture. Are patches for the PPC 
>> architecture still processed?
>>
>> I know that the ppc-architecture is being phased out, but for the moment 
>> I am stuck with it, as the board I am working with is not supported in 
>> the powerpc architecture. 
>>     
>
> If you've having to submit or look for patches, it sounds like it isn't
> working with the obsolete arch/ppc either. Time to update, perhaps?
>
>   
Well, this is one of the minor issues I have with the ppc architecture, 
but I am quite happy with it. Even for this I could make a workaround, 
but I guess this is something that other might stumble upon.

I would like to move to powerpc, but for the moment there is no official 
support for powerpc, for ppc there is, but I don't have the time to move 
this to powerpc. So I am afraid I don't have much choice.

Kind regards,

-- 
Johan Borkhuis                                  Dutch Space BV
email:        j.borkhuis@dutchspace.nl          Newtonweg 1
phone:        071-5245788                       Leiden
fax:          071-5245499                       The Netherlands

Re: Patches for ppc?

[David Woodhouse]

On Fri, 2007-08-17 at 16:36 +0200, Johan Borkhuis wrote:
> Well, this is one of the minor issues I have with the ppc architecture, 
> but I am quite happy with it. Even for this I could make a workaround, 
> but I guess this is something that other might stumble upon.
> 
> I would like to move to powerpc, but for the moment there is no official 
> support for powerpc, for ppc there is, but I don't have the time to move 
> this to powerpc. So I am afraid I don't have much choice. 

It's times like this you suddenly realise you should have paid the extra
cash for a licence which allows you access to the source code?

-- 
dwmw2

Re: Patches for ppc?

[Johan Borkhuis]

David Woodhouse wrote:
> On Fri, 2007-08-17 at 16:36 +0200, Johan Borkhuis wrote:
>   
>> Well, this is one of the minor issues I have with the ppc architecture, 
>> but I am quite happy with it. Even for this I could make a workaround, 
>> but I guess this is something that other might stumble upon.
>>
>> I would like to move to powerpc, but for the moment there is no official 
>> support for powerpc, for ppc there is, but I don't have the time to move 
>> this to powerpc. So I am afraid I don't have much choice. 
>>     
>
> It's times like this you suddenly realise you should have paid the extra
> cash for a licence which allows you access to the source code?
>
>   
That is not the problem: we have access to all the sources, but I am 
waiting for the official support for the powerpc architecure. I am using 
an MVME3100 board from Motorola and I know that they are working on it, 
but it is not released (yet).

Kind regards,
    Johan Borkhuis

Re: Patches for ppc?

[Satya]

hi,
what's the issue with arch/ppc again? why is it being phased out? I am
working with the IBM Blue Gene/L which is based on ppc440. I need to
get a patch in too! :)

I noticed that head_44x.S has been copied to arch/powerpc/kernel in
the current head tree, but is it functional yet? has everything been
moved to arch/powerpc ? how about the include files ?

thanks!
satya.

On 8/17/07, Johan Borkhuis <j.borkhuis@dutchspace.nl> wrote:
> David Woodhouse wrote:
> > On Fri, 2007-08-17 at 16:36 +0200, Johan Borkhuis wrote:
> >
> >> Well, this is one of the minor issues I have with the ppc architecture,
> >> but I am quite happy with it. Even for this I could make a workaround,
> >> but I guess this is something that other might stumble upon.
> >>
> >> I would like to move to powerpc, but for the moment there is no official
> >> support for powerpc, for ppc there is, but I don't have the time to move
> >> this to powerpc. So I am afraid I don't have much choice.
> >>
> >
> > It's times like this you suddenly realise you should have paid the extra
> > cash for a licence which allows you access to the source code?
> >
> >
> That is not the problem: we have access to all the sources, but I am
> waiting for the official support for the powerpc architecure. I am using
> an MVME3100 board from Motorola and I know that they are working on it,
> but it is not released (yet).
>
> Kind regards,
>     Johan Borkhuis
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>

Re: Patches for ppc?

[David Gibson]

On Fri, Aug 17, 2007 at 06:28:50PM -0500, Satya wrote:
> hi,
> what's the issue with arch/ppc again? why is it being phased out? I
> am

It's a crusty, nasty, old codebase that we want to replace with the
newer and nicer arch/powerpc.

> working with the IBM Blue Gene/L which is based on ppc440. I need to
> get a patch in too! :)
> 
> I noticed that head_44x.S has been copied to arch/powerpc/kernel in
> the current head tree, but is it functional yet? has everything been
> moved to arch/powerpc ? how about the include files ?

It's not a question of indivudual files being copied over - things are
done differently in arch/powerpc.  Things are gradually being ported
over to arch/powerpc as people get the time - that's why arch/ppc
isn't gone yet.  440 support is now in arch/powerpc, but is not yet
complete:  it works, but is missing some fairly important device
support (RTC and PCI are the most prominent).

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: Patches for ppc?

[Segher Boessenkool]

> It's not a question of indivudual files being copied over - things are
> done differently in arch/powerpc.  Things are gradually being ported
> over to arch/powerpc as people get the time - that's why arch/ppc
> isn't gone yet.

And to be blunt, one of the points of arch/powerpc vs. arch/ppc is
to actually leave behind some stuff.  "If no one ports it, no one
wants it".


Segher

Re: Patches for ppc?

[Phil Terry]

On Tue, 2007-08-21 at 17:14 +0200, Segher Boessenkool wrote:
> > It's not a question of indivudual files being copied over - things are
> > done differently in arch/powerpc.  Things are gradually being ported
> > over to arch/powerpc as people get the time - that's why arch/ppc
> > isn't gone yet.
> 
> And to be blunt, one of the points of arch/powerpc vs. arch/ppc is
> to actually leave behind some stuff.  "If no one ports it, no one
> wants it".

So am I alone in getting a mixed message from "Linux community" to
"embedded community"? 

On the one hand we have people like GKH telling embedded people to stop
being private company/device specific forks but to submit their hardware
to the tree where it will be supported "for free" by the kernel hackers,
saving us the "chore" of supporting "our" code through all the kernel
changes and forever chasing it.

On the other hand we have people telling us that because we are too lazy
to support "our" code the kernel guys aren't going to pull it forward
for us.

So in fact people 3rd party people like me are in between real problems,
we base our code on say a Freescale chip, who submit to the kernel to
save their support issues and we base our code on that. Now, the
Freescale guys are too busy porting their "latest" chips across the
PPC/Powerpc divide to port the "old" stuff so it gets "left behind".
That old stuff is still selling and the people who based code on it had
the expectation that the code would continue to be supported. So now I'm
being told not only to "port my stuff or lose it" but now also port
freescale's stuff or lose it.

And then we get beaten up because we "stayed" with "ancient stuff" like
2.6.21!!!

Not picking on Freescale, or Segher, just trying to wave the flag, lots
of people want it, they are just not all in a position to save it
because we "embedded" people are by nature a fractured community of
niche players with products that don't turn over with out customers
every six months, some people will want to buy a product for years...

And yes I do understand the "Linux kernel hackers are nothing more than
a group of diverse people from many companies so why is embedded any
different" argument, I just don't have an answer right now other than it
is.

Cheers
Phil

> 
> 
> Segher
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
> 
> 

Re: Patches for ppc?

[Josh Boyer]

On Tue, 21 Aug 2007 09:11:24 -0700
Phil Terry <pterry@micromemory.com> wrote:

> On Tue, 2007-08-21 at 17:14 +0200, Segher Boessenkool wrote:
> > > It's not a question of indivudual files being copied over - things are
> > > done differently in arch/powerpc.  Things are gradually being ported
> > > over to arch/powerpc as people get the time - that's why arch/ppc
> > > isn't gone yet.
> > 
> > And to be blunt, one of the points of arch/powerpc vs. arch/ppc is
> > to actually leave behind some stuff.  "If no one ports it, no one
> > wants it".
> 
> So am I alone in getting a mixed message from "Linux community" to
> "embedded community"? 

I don't think so..

> On the one hand we have people like GKH telling embedded people to stop
> being private company/device specific forks but to submit their hardware
> to the tree where it will be supported "for free" by the kernel hackers,
> saving us the "chore" of supporting "our" code through all the kernel
> changes and forever chasing it.

Yes.  Just submit it to the arch/powerpc tree instead of arch/ppc.  But
this is only an issue for the _initial_ submit, and only while the
merge is on-going.

> On the other hand we have people telling us that because we are too lazy
> to support "our" code the kernel guys aren't going to pull it forward
> for us.

That's more of a issue for _existing_ code, not new code.

> So in fact people 3rd party people like me are in between real problems,
> we base our code on say a Freescale chip, who submit to the kernel to
> save their support issues and we base our code on that. Now, the
> Freescale guys are too busy porting their "latest" chips across the
> PPC/Powerpc divide to port the "old" stuff so it gets "left behind".

Or maybe it's just not ported yet?

> That old stuff is still selling and the people who based code on it had
> the expectation that the code would continue to be supported. So now I'm
> being told not only to "port my stuff or lose it" but now also port
> freescale's stuff or lose it.

Well... it's not really going away until June 2008.  There's time.

josh

Re: Patches for ppc?

[Kumar Gala]

On Aug 21, 2007, at 11:11 AM, Phil Terry wrote:

> On Tue, 2007-08-21 at 17:14 +0200, Segher Boessenkool wrote:
>>> It's not a question of indivudual files being copied over -  
>>> things are
>>> done differently in arch/powerpc.  Things are gradually being ported
>>> over to arch/powerpc as people get the time - that's why arch/ppc
>>> isn't gone yet.
>>
>> And to be blunt, one of the points of arch/powerpc vs. arch/ppc is
>> to actually leave behind some stuff.  "If no one ports it, no one
>> wants it".
>
> So am I alone in getting a mixed message from "Linux community" to
> "embedded community"?
>
> On the one hand we have people like GKH telling embedded people to  
> stop
> being private company/device specific forks but to submit their  
> hardware
> to the tree where it will be supported "for free" by the kernel  
> hackers,
> saving us the "chore" of supporting "our" code through all the kernel
> changes and forever chasing it.
>
> On the other hand we have people telling us that because we are too  
> lazy
> to support "our" code the kernel guys aren't going to pull it forward
> for us.

There is clearly a balance here.  While I don't think too many people  
are going to disagree with GKH intent, there is a practicality about  
it.  If no kernel hacker has access to a particular board that was  
supported in arch/ppc and no one seems to care about it than it seems  
to be a candidate to not move forward.

> So in fact people 3rd party people like me are in between real  
> problems,
> we base our code on say a Freescale chip, who submit to the kernel to
> save their support issues and we base our code on that. Now, the
> Freescale guys are too busy porting their "latest" chips across the
> PPC/Powerpc divide to port the "old" stuff so it gets "left behind".
> That old stuff is still selling and the people who based code on it  
> had
> the expectation that the code would continue to be supported. So  
> now I'm
> being told not only to "port my stuff or lose it" but now also port
> freescale's stuff or lose it.

If there is some specific freescale board/chip that is being left  
behind that you're concerned about please let me know.

> And then we get beaten up because we "stayed" with "ancient stuff"  
> like
> 2.6.21!!!
>
> Not picking on Freescale, or Segher, just trying to wave the flag,  
> lots
> of people want it, they are just not all in a position to save it
> because we "embedded" people are by nature a fractured community of
> niche players with products that don't turn over with out customers
> every six months, some people will want to buy a product for years...
>
> And yes I do understand the "Linux kernel hackers are nothing more  
> than
> a group of diverse people from many companies so why is embedded any
> different" argument, I just don't have an answer right now other  
> than it
> is.

I'd ask you to mention specific boards/chip/functionality rather than  
generic statements so we can actual be aware of things we're  
forgetting or are important to people that we are not aware of.

The fact that arch/ppc is 'dead' has been posted on the lists  
numerous times to give people the opportunity to let us all know  
what's important to people.

- k

Re: Patches for ppc?

[Phil Terry]

Ooops,

Sorry guys, this is probably the wrong forum and I didn't mean to sound
like I was trashing anyones efforts here. 

As I said, I'm not picking on Freescale or anyone else on this list. I'm
just trying to understand this process as an embedded developer who
works at companies which use code bases provided by other 3rd parties. 

I understand its an ongoing process, change is the only constant. So I
try not to whine that my particular board/chip/issue isn't fixed in the
latest kernel, patch, support package and I try to patch things up and
make progress on *my* project by pulling  bits and pieces together
hoping that my stuff will eventually get fixed. 

But then I see comments from other people who I assume are in the same
boat and the response is, "no one uses that. Theres no demand for it.
We're dropping that" Its like when I go to a pub in England and ask for
a pint of "mild" ale. "We don't serve that here, there's no demand for
it." Huh, didn't I just demand it? So then I get worried, how do I know
who's plan and schedule include/excludes my board/chip/issue?

I was trying to raise that generic issue, which is why I tried to be
generic. Didn't mean to gore anyones ox.

Cheers
Phil (who now has to drink American Beer.....)

On Tue, 2007-08-21 at 11:40 -0500, Kumar Gala wrote:
> On Aug 21, 2007, at 11:11 AM, Phil Terry wrote:
> 
> > On Tue, 2007-08-21 at 17:14 +0200, Segher Boessenkool wrote:
> >>> It's not a question of indivudual files being copied over -  
> >>> things are
> >>> done differently in arch/powerpc.  Things are gradually being ported
> >>> over to arch/powerpc as people get the time - that's why arch/ppc
> >>> isn't gone yet.
> >>
> >> And to be blunt, one of the points of arch/powerpc vs. arch/ppc is
> >> to actually leave behind some stuff.  "If no one ports it, no one
> >> wants it".
> >
> > So am I alone in getting a mixed message from "Linux community" to
> > "embedded community"?
> >
> > On the one hand we have people like GKH telling embedded people to  
> > stop
> > being private company/device specific forks but to submit their  
> > hardware
> > to the tree where it will be supported "for free" by the kernel  
> > hackers,
> > saving us the "chore" of supporting "our" code through all the kernel
> > changes and forever chasing it.
> >
> > On the other hand we have people telling us that because we are too  
> > lazy
> > to support "our" code the kernel guys aren't going to pull it forward
> > for us.
> 
> There is clearly a balance here.  While I don't think too many people  
> are going to disagree with GKH intent, there is a practicality about  
> it.  If no kernel hacker has access to a particular board that was  
> supported in arch/ppc and no one seems to care about it than it seems  
> to be a candidate to not move forward.
> 
> > So in fact people 3rd party people like me are in between real  
> > problems,
> > we base our code on say a Freescale chip, who submit to the kernel to
> > save their support issues and we base our code on that. Now, the
> > Freescale guys are too busy porting their "latest" chips across the
> > PPC/Powerpc divide to port the "old" stuff so it gets "left behind".
> > That old stuff is still selling and the people who based code on it  
> > had
> > the expectation that the code would continue to be supported. So  
> > now I'm
> > being told not only to "port my stuff or lose it" but now also port
> > freescale's stuff or lose it.
> 
> If there is some specific freescale board/chip that is being left  
> behind that you're concerned about please let me know.
> 
> > And then we get beaten up because we "stayed" with "ancient stuff"  
> > like
> > 2.6.21!!!
> >
> > Not picking on Freescale, or Segher, just trying to wave the flag,  
> > lots
> > of people want it, they are just not all in a position to save it
> > because we "embedded" people are by nature a fractured community of
> > niche players with products that don't turn over with out customers
> > every six months, some people will want to buy a product for years...
> >
> > And yes I do understand the "Linux kernel hackers are nothing more  
> > than
> > a group of diverse people from many companies so why is embedded any
> > different" argument, I just don't have an answer right now other  
> > than it
> > is.
> 
> I'd ask you to mention specific boards/chip/functionality rather than  
> generic statements so we can actual be aware of things we're  
> forgetting or are important to people that we are not aware of.
> 
> The fact that arch/ppc is 'dead' has been posted on the lists  
> numerous times to give people the opportunity to let us all know  
> what's important to people.
> 
> - k
> 
> 

Re: Patches for ppc?

[Scott Wood]

On Tue, Aug 21, 2007 at 10:12:17AM -0700, Phil Terry wrote:
> Sorry guys, this is probably the wrong forum and I didn't mean to sound
> like I was trashing anyones efforts here. 

I don't think it was taken that way -- rather, we want to know what
hardware people are still using with recent kernels.  Greg KH's "offer"
was a bit over-idealistic; hacker-hours are a finite resource, and
there's not much point spending it on hardware which is primarily
installed in landfills. :-)

The offer seems to be founded on the assumption that the user base of a
given device among kernel hackers is proportional to the user base in the
general population, which is less likely to be true with embedded
hardware.  Thus, we need feedback on which hardware is being actively
developed on.

> But then I see comments from other people who I assume are in the same
> boat and the response is, "no one uses that. Theres no demand for it.
> We're dropping that" Its like when I go to a pub in England and ask for
> a pint of "mild" ale. "We don't serve that here, there's no demand for
> it." Huh, didn't I just demand it?

Yes, and if they found themselves repeating that answer on a regular
basis, they might decide to add a tap.  Again, non-finite resources. :-)

> So then I get worried, how do I know who's plan and schedule
> include/excludes my board/chip/issue?

You ask.

> Cheers
> Phil (who now has to drink American Beer.....)

Mmm... beer...

I just *hate* it when I have to drink a nice Rogue, Stone, Breckenridge,
Victory, etc. :-)

-Scott

Re: Patches for ppc?

[Segher Boessenkool]

> So then I get worried, how do I know
> who's plan and schedule include/excludes my board/chip/issue?

The arch/ppc -> arch/powerpc changeover is exceptional for various
reasons.

First, it is a huge change taking multiple years to complete.
Only recently it has been decided when to finally drop arch/ppc
completely; and that's not going to happen until almost a year
from now.

Secondly, it really does change many things at the core.  It
is almost impossible for people without in-depth knowledge of
specific hardware too correctly port support code for that
hardware over those core changes, and certainly impossible to
actually test the ported code.  So the only sane approach was
to only port the hardware support code people _did_ have access
to.  Which isn't to say the other platforms still "in demand"
will be left behind of course, some are still being ported over,
and there is nothing preventing such a port even after arch/ppc
is dead and gone either.

Thirdly, Greg KH is talking more about generic drivers (PCI
device drivers, for example) than about low-level platform code;
at least that's my impression.  The good news is that in the
arch/powerpc world much more of the low-level stuff will be
abstracted away, or at least sanely abstracted at all, so in
the future we won't have all that many problems making even
the biggest core changes anymore.

> I was trying to raise that generic issue, which is why I tried to be
> generic. Didn't mean to gore anyones ox.

Don't worry, you didn't offend anyone as far as I can see :-)

All of the "more generic" stuff (e.g., CPU/SoC support) should
be ported over soon enough (if not, shout); some more specific
stuff (support for some specific board, etc.) you will have to
do yourself, or find someone else to do it for you.  And you can
always ask for help here, we're all very helpful and friendly
here (if you believe that ;-) )


Segher

Re: Patches for ppc?

[Linas Vepstas]

On Tue, Aug 21, 2007 at 09:11:24AM -0700, Phil Terry wrote:
> On Tue, 2007-08-21 at 17:14 +0200, Segher Boessenkool wrote:
> > > It's not a question of indivudual files being copied over - things are
> > > done differently in arch/powerpc.  Things are gradually being ported
> > > over to arch/powerpc as people get the time - that's why arch/ppc
> > > isn't gone yet.
> > 
> > And to be blunt, one of the points of arch/powerpc vs. arch/ppc is
> > to actually leave behind some stuff.  "If no one ports it, no one
> > wants it".
> 
> So am I alone in getting a mixed message from "Linux community" to
> "embedded community"? 
> 
> On the one hand we have people like GKH telling embedded people to stop
> being private company/device specific forks but to submit their hardware
> to the tree where it will be supported "for free" by the kernel hackers,
> saving us the "chore" of supporting "our" code through all the kernel
> changes and forever chasing it.
> 
> On the other hand we have people telling us that because we are too lazy
> to support "our" code the kernel guys aren't going to pull it forward
> for us.

You've got to keep things in perspective. Some devices do get old and
stale, and no one ever uses them any more. These devices do disappear
from the kernel tree over time. Its not unreasonable to have a "sunset"
policy for old stuff.  Some devices continue to have an active, interested 
community that helps maintain them.

Some kernel changes are big, and some are small. Sometimes big changes
are so big that they can't be done without having everybody pitch in
and help out.  The transition from ppc to powerpc is like that.  To 
cross over such humps, its not just a matter of laziness -- I have
enough work to keep ten of me occupied -- but its also access to
equipment: someone needs to verify that old hardware still works 
with the new changes.  Embedded is particularly dicey: there are so 
many platforms, most developers will never have seen the one in question.

> So in fact people 3rd party people like me are in between real problems,
> we base our code on say a Freescale chip, who submit to the kernel to
> save their support issues and we base our code on that. Now, the
> Freescale guys are too busy porting their "latest" chips across the
> PPC/Powerpc divide to port the "old" stuff so it gets "left behind".
> That old stuff is still selling and the people who based code on it had
> the expectation that the code would continue to be supported. 

For example, Redhat RHEL 4 is based on the 2.6.9 kernel, and god
help me I'm *still* posting patches and fixes to that, although
its a rather unpleasent task. There's a real economic motivation
to do this  --- and its called "support".  Someone out there cares
enough to want this old stuff to work across a whole range of h/w.

> So now I'm
> being told not only to "port my stuff or lose it" but now also port
> freescale's stuff or lose it.
> 
> And then we get beaten up because we "stayed" with "ancient stuff" like
> 2.6.21!!!

You get beaten up if you are trying to get new stuff to work on old
code bases -- for good reason. 

> Not picking on Freescale, or Segher, just trying to wave the flag, lots
> of people want it, they are just not all in a position to save it
> because we "embedded" people are by nature a fractured community of
> niche players with products that don't turn over with out customers
> every six months, some people will want to buy a product for years...

RHEL 4 is several years old, and it will be around for years more,
and its based on the 2.6.9 kernel, and, if it works for your customers,
they should use that. Once you've got a working software installation,
don't upgrade it! Upgrades do break things, so if it works, don't mess
with it.

But if you are building a new product, and adding new features, then
it does not make sense to try to do that to an old kernel.  And, yes,
there's a non-trivial effort to stay current and surf the cutting edge.
And, yes, there can be dangerous rip-tides, like the ppc->powerpc
migration, that can catch ahold of you.

--linas