Is it good for a PDA fs?

Is it good for a PDA fs?

[The Doctor What]

Having just bought a Sharp Zaurus with a 64meg MMC and a 256 CF, my
mind instantly jumps to the question, can it be used to pick up
chicks?

When I was done with that avenue of thought, I wondered if it's
worth it to figure out how to build my own kernel just to add
reiserfs to it.

I know about it's handiness with journalling, etc. and that'd be
useful for the occasional glitches I've had.

Does ReiserFS has anything that is more useful or less usefull for
such a small memory application?

Ciao!

-- 
"If A equals success, then the formula is A = X + Y + Z.  X is work.  Y is
play.  Z is keep your mouth shut."
		-- Albert Einstein 

The Doctor What: A really hip dude               http://docwhat.gerf.org/
docwhat@gerf.org                                                   KF6VNC

Re: Is it good for a PDA fs?

[Chris Dukes]

On Sat, Jun 22, 2002 at 11:52:07AM -0500, The Doctor What wrote:
> Having just bought a Sharp Zaurus with a 64meg MMC and a 256 CF, my
> mind instantly jumps to the question, can it be used to pick up
> chicks?
> 
> When I was done with that avenue of thought, I wondered if it's
> worth it to figure out how to build my own kernel just to add
> reiserfs to it.
> 
> I know about it's handiness with journalling, etc. and that'd be
> useful for the occasional glitches I've had.
> 
> Does ReiserFS has anything that is more useful or less usefull for
> such a small memory application?

Standard journalling techniques just fry a portion of the compact flash
faster.  The tail merging might save space, but I would like to see
a study of its effects on the longevity of compact flash.

I think, but could be mistaken, than you want JFFS or JFFS2.

-- 
Chris Dukes
The Information Technology field is similar to a Marx Brothers sketch.
As a sysadmin, I fill in for Harpo Marx.  -- me.

Re: Is it good for a PDA fs?

[Hans Reiser]

Chris Dukes wrote:

>On Sat, Jun 22, 2002 at 11:52:07AM -0500, The Doctor What wrote:
>  
>
>>Having just bought a Sharp Zaurus with a 64meg MMC and a 256 CF, my
>>mind instantly jumps to the question, can it be used to pick up
>>chicks?
>>
>>When I was done with that avenue of thought, I wondered if it's
>>worth it to figure out how to build my own kernel just to add
>>reiserfs to it.
>>
>>I know about it's handiness with journalling, etc. and that'd be
>>useful for the occasional glitches I've had.
>>
>>Does ReiserFS has anything that is more useful or less usefull for
>>such a small memory application?
>>    
>>
>
>Standard journalling techniques just fry a portion of the compact flash
>faster.  The tail merging might save space, but I would like to see
>a study of its effects on the longevity of compact flash.
>
>I think, but could be mistaken, than you want JFFS or JFFS2.
>
>  
>
I also have a sharp zaurus with 256M CF......


Currently the CF uses VFAT, yes?

I bet it has the same wear issues, and no space savings....

The zaurus has a non-standard kernel though, and it is based off of some 
rather old release (2.4.4?).  You would want to apply their kernel 
extensions to 2.4.18 or later I think  before using reiserfs....  If you 
do so, and get it working, let me know, the only reason I haven't used 
reiserfs on my CF is that I don't know where to get a recent kernel with 
their (presumably useful to the PDA) extensions....

You know, using a kernel that old seems like a really bad idea, the 
early 2.4s were simply beta-tests in my mind, I'd like to upgrade for 
reasons not just filesystems.....

Marcelo is doing a great job with keeping 2.4 stable.....

-- 
Hans

Re: Is it good for a PDA fs?

[Oleg Drokin]

Hello!

On Sat, Jun 22, 2002 at 09:50:33PM +0400, Hans Reiser wrote:
> >faster.  The tail merging might save space, but I would like to see
> >a study of its effects on the longevity of compact flash.
> >I think, but could be mistaken, than you want JFFS or JFFS2.
> I also have a sharp zaurus with 256M CF......
> Currently the CF uses VFAT, yes?
> I bet it has the same wear issues, and no space savings....

CF is different story. They fight level of wearing in underlying layer.
And on high level they emulate IDE.
Zaurus also have compact flash memory directly accessible by CPU, that
one can be access via MTD devices in Linux. There you can actually
control wering by yourself. But reiserfs (v3) is not very suited for that
JFFS & JFFS2 do.

And you can format CF with reiserfs without any problems
But do not expect that windows or digital cameras would understand
that ;)
Also - in conjunctions with PDAs - reiserfs is quite memory (RAM) hungry,
so using it on 32M ram box is somewhat questionable.

And static 32M journal (that's 13% off your CF size, btw)

> The zaurus has a non-standard kernel though, and it is based off of some 
> rather old release (2.4.4?).  You would want to apply their kernel 
> extensions to 2.4.18 or later I think  before using reiserfs....  If you 
> do so, and get it working, let me know, the only reason I haven't used 
> reiserfs on my CF is that I don't know where to get a recent kernel with 
> their (presumably useful to the PDA) extensions....

Building ARM kernels is easy.
I always build kernels for my ARM toys myself.

and I bet that Zaurus kernel is based off some -rmk kernel with
may be minor patches (sources of these should be available at Sharp
of course).
So getting (making) new kernel should be trivial.
Especially if they use some decent bootloader that allows to have
several kernels.

> Marcelo is doing a great job with keeping 2.4 stable.....

If only he'd release 2.4.19 soon...

But he is probably out for kernel con too... So no new 2.4 kernel
for a while it seems.

Bye,
    Oleg

Re: Is it good for a PDA fs?

[Hans Reiser]

Oleg Drokin wrote:

>Hello!
>
>On Sat, Jun 22, 2002 at 09:50:33PM +0400, Hans Reiser wrote:
>  
>
>>>faster.  The tail merging might save space, but I would like to see
>>>a study of its effects on the longevity of compact flash.
>>>I think, but could be mistaken, than you want JFFS or JFFS2.
>>>      
>>>
>>I also have a sharp zaurus with 256M CF......
>>Currently the CF uses VFAT, yes?
>>I bet it has the same wear issues, and no space savings....
>>    
>>
>
>CF is different story. They fight level of wearing in underlying layer.
>
Meaning that they hide it in the device driver, and the FS does not need 
to be aware of it?

>And on high level they emulate IDE.
>Zaurus also have compact flash memory directly accessible by CPU, that
>one can be access via MTD devices in Linux. There you can actually
>control wering by yourself. But reiserfs (v3) is not very suited for that
>JFFS & JFFS2 do.
>
>And you can format CF with reiserfs without any problems
>But do not expect that windows or digital cameras would understand
>that ;)
>Also - in conjunctions with PDAs - reiserfs is quite memory (RAM) hungry,
>so using it on 32M ram box is somewhat questionable.
>
>And static 32M journal (that's 13% off your CF size, btw)
>
Our journal resizing patch is waiting for the next pre1 to go in, yes?

Regardless of all of this, it really would not surprise me if a 
filesystem design for CFs does a better job than we do at CFs.....

It is so annoying that it is taking so long for 2.4.19.....  I respect 
it, and it is probably the right thing for the users, but our 
performance is suffering a lot for the lack of these patches in the 
mainstream kernel.....

>
>  
>
>>The zaurus has a non-standard kernel though, and it is based off of some 
>>rather old release (2.4.4?).  You would want to apply their kernel 
>>extensions to 2.4.18 or later I think  before using reiserfs....  If you 
>>do so, and get it working, let me know, the only reason I haven't used 
>>reiserfs on my CF is that I don't know where to get a recent kernel with 
>>their (presumably useful to the PDA) extensions....
>>    
>>
>
>Building ARM kernels is easy.
>I always build kernels for my ARM toys myself.
>
>and I bet that Zaurus kernel is based off some -rmk kernel with
>may be minor patches (sources of these should be available at Sharp
>of course).
>So getting (making) new kernel should be trivial.
>
I think I probably care more about downloading and trying the latest 
kalendar than installing a new kernel on it.;-)   It is nice to have ssh 
running on it now....   After our July 11 DARPA presentation though I 
will recompile the kernel, and maybe try reiserfs on an MMC, and test 
how the user interface and docs are for journal relocation/resizing.....

>Especially if they use some decent bootloader that allows to have
>several kernels.
>
>  
>


-- 
Hans

Re: Is it good for a PDA fs?

[Oleg Drokin]

Hello!

On Sun, Jun 23, 2002 at 12:56:30AM +0400, Hans Reiser wrote:

> >CF is different story. They fight level of wearing in underlying layer.
> Meaning that they hide it in the device driver, and the FS does not need 
> to be aware of it?

Yes. Otherwise CF media would be pretty much useless in conjunction with VFAT.

> >And you can format CF with reiserfs without any problems
> >But do not expect that windows or digital cameras would understand
> >that ;)
> >Also - in conjunctions with PDAs - reiserfs is quite memory (RAM) hungry,
> >so using it on 32M ram box is somewhat questionable.
> >And static 32M journal (that's 13% off your CF size, btw)
> Our journal resizing patch is waiting for the next pre1 to go in, yes?

Yes.

> Regardless of all of this, it really would not surprise me if a 
> filesystem design for CFs does a better job than we do at CFs.....

I am not aware of any CF-centric filesystem. Because CF represents itself as
IDE device.
Directly accessible flash is a different matter of course.

> >Building ARM kernels is easy.
> >I always build kernels for my ARM toys myself.
> >and I bet that Zaurus kernel is based off some -rmk kernel with
> >may be minor patches (sources of these should be available at Sharp
> >of course).
> >So getting (making) new kernel should be trivial.
> I think I probably care more about downloading and trying the latest 
> kalendar than installing a new kernel on it.;-)   It is nice to have ssh 

Yes, exactly. I do not see how you (or any other user) would benefit from
using anything but vfat in CF, but disadvantages are pretty clear.

Bye,
    Oleg

Re: Is it good for a PDA fs?

[Hans Reiser]

Oleg Drokin wrote:

>Hello!
>
>On Sun, Jun 23, 2002 at 12:56:30AM +0400, Hans Reiser wrote:
>
>  
>
>>>CF is different story. They fight level of wearing in underlying layer.
>>>      
>>>
>>Meaning that they hide it in the device driver, and the FS does not need 
>>to be aware of it?
>>    
>>
>
>Yes. Otherwise CF media would be pretty much useless in conjunction with VFAT.
>
Good thinking on their part.  Sure makes our job easier....

>  
>
>
>  
>
>>>Building ARM kernels is easy.
>>>I always build kernels for my ARM toys myself.
>>>and I bet that Zaurus kernel is based off some -rmk kernel with
>>>may be minor patches (sources of these should be available at Sharp
>>>of course).
>>>So getting (making) new kernel should be trivial.
>>>      
>>>
>>I think I probably care more about downloading and trying the latest 
>>kalendar than installing a new kernel on it.;-)   It is nice to have ssh 
>>    
>>
>
>Yes, exactly. I do not see how you (or any other user) would benefit from
>using anything but vfat in CF, but disadvantages are pretty clear.
>
Space would be saved if the journal was shrunk in size....

>
>Bye,
>    Oleg
>
>
>  
>


-- 
Hans

Re: Is it good for a PDA fs?

[Oleg Drokin]

Hello!

On Sun, Jun 23, 2002 at 11:18:02AM +0400, Hans Reiser wrote:

> >>I think I probably care more about downloading and trying the latest 
> >>kalendar than installing a new kernel on it.;-)   It is nice to have ssh 
> >Yes, exactly. I do not see how you (or any other user) would benefit from
> >using anything but vfat in CF, but disadvantages are pretty clear.
> Space would be saved if the journal was shrunk in size....

VFAT (fat32) addresses 512 byte blocks while reiserfs now addresses
4096 byte blocks. (not this can be theoretically decreased to 1024 byte blocks
with a patch, but in this case tree will grow very quickly and will reach
height of 5 way too soon). And while on reiserfs tails are not packed
for files over 16K (and not packed for smaller files in some cases to to avoid
"seeks"), it is impossible to spend more than 511 bytes of unused space
on vfat no matter what file size is. (vs max of 4095 bytes wasted on
reiserfs in unlucky case).
So right now I do not see noticeable space savings.
Of course I have not performed precise measurements so this is only
a theory.

Bye,
    Oleg

Re: Is it good for a PDA fs?

[Hans Reiser]

Oleg Drokin wrote:

>Hello!
>
>On Sun, Jun 23, 2002 at 11:18:02AM +0400, Hans Reiser wrote:
>
>  
>
>>>>I think I probably care more about downloading and trying the latest 
>>>>kalendar than installing a new kernel on it.;-)   It is nice to have ssh 
>>>>        
>>>>
>>>Yes, exactly. I do not see how you (or any other user) would benefit from
>>>using anything but vfat in CF, but disadvantages are pretty clear.
>>>      
>>>
>>Space would be saved if the journal was shrunk in size....
>>    
>>
>
>VFAT (fat32) addresses 512 byte blocks while reiserfs now addresses
>4096 byte blocks. (not this can be theoretically decreased to 1024 byte blocks
>with a patch, but in this case tree will grow very quickly and will reach
>height of 5 way too soon). And while on reiserfs tails are not packed
>for files over 16K (and not packed for smaller files in some cases to to avoid
>"seeks"), it is impossible to spend more than 511 bytes of unused space
>on vfat no matter what file size is. (vs max of 4095 bytes wasted on
>reiserfs in unlucky case).
>So right now I do not see noticeable space savings.
>
End of file space wastage is critical for small files not large ones. 
 For small files we do much better than VFAT.

I don't know what overhead they have for various kinds of metadata 
though.....

It is probably true that VFAT does a better job for CF than for usual 
hard drives though.

>Of course I have not performed precise measurements so this is only
>a theory.
>
>Bye,
>    Oleg
>
>
>  
>


-- 
Hans

Re: Is it good for a PDA fs?

[The Doctor What]

[-- Attachment #1: Type: text/plain, Size: 512 bytes --]

* Oleg Drokin (green@namesys.com) [020623 01:50]:
> > Meaning that they hide it in the device driver, and the FS does not need 
> > to be aware of it?
> 
> Yes. Otherwise CF media would be pretty much useless in conjunction with VFAT.

Is this true of the MMC cards too? (And the SD, I guess).

Ciao!

-- 
Any program which runs right is obsolete.

The Doctor What: Da Man                          http://docwhat.gerf.org/
docwhat@gerf.org                                                   KF6VNC

[-- Attachment #2: Type: application/pgp-signature, Size: 232 bytes --]

Re: Re: Is it good for a PDA fs?

[Oleg Drokin]

Hello!

On Tue, Jun 25, 2002 at 12:35:13PM -0500, The Doctor What wrote:
> > > Meaning that they hide it in the device driver, and the FS does not need 
> > > to be aware of it?
> > Yes. Otherwise CF media would be pretty much useless in conjunction with VFAT.
> Is this true of the MMC cards too? (And the SD, I guess).

I do not know about MMC, and SD is so badly proprietary, you cannot
learn anything about these without spending rest of your days in jail
because of DMCA violations.

Bye,
    Oleg

Re: Re: Is it good for a PDA fs?

[Olivier]

[-- Attachment #1: Type: text/plain, Size: 339 bytes --]

On Wed, 26 Jun 2002 08:56:02 +0400
"Oleg Drokin" <green@namesys.com> wrote:

> I do not know about MMC, and SD is so badly proprietary, you cannot
> learn anything about these without spending rest of your days in jail
> because of DMCA violations.

DMCA only holds in the USA, so don't worry about it if you're abroad

regards,
	Olivier


[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]

Re: Re: Is it good for a PDA fs?

[Jose Alberto Guzman]

remember Skylarov...

Olivier wrote:

>On Wed, 26 Jun 2002 08:56:02 +0400
>"Oleg Drokin" <green@namesys.com> wrote:
>
>>I do not know about MMC, and SD is so badly proprietary, you cannot
>>learn anything about these without spending rest of your days in jail
>>because of DMCA violations.
>>
>
>DMCA only holds in the USA, so don't worry about it if you're abroad
>
>regards,
>	Olivier
>

Re: Re: Is it good for a PDA fs?

[Chris Dukes]

On Fri, Jun 28, 2002 at 06:22:06PM -0500, Jose Alberto Guzman wrote:
> remember Skylarov...

Skylarov also made the mistake of visiting the US.

-- 
Chris Dukes
The Information Technology field is similar to a Marx Brothers sketch.
As a sysadmin, I fill in for Harpo Marx.  -- me.

Re: Re: Is it good for a PDA fs?

[Oleg Drokin]

Hello!

On Fri, Jun 28, 2002 at 10:50:36PM +0200, Olivier wrote:
> > I do not know about MMC, and SD is so badly proprietary, you cannot
> > learn anything about these without spending rest of your days in jail
> > because of DMCA violations.
> DMCA only holds in the USA, so don't worry about it if you're abroad

Do you remember the Slklyarov's case?

Bye,
    Oleg