RE: [ECOS] FLASH file system

RE: [ECOS] FLASH file system

[Simpkins, Andy]

Andrew,

What I am looking for is something like the following...

- Ability to read and write files to FLASH
- Because BLOCK size in flash is typically quite large (>64K) then it is
desirable to split blocks into sub-blocks of a more reasonable size.  
- This now leaves the problem of erasing (as the smallest erase size is 1
block).
- By leaving 1 Block free space in the file system at all times it is
possible to 'juggle' data around (i.e. defragmenter) such that sub-blocks
no-longer in use may be freed up for re-use.
- Obviously this will require 1 (or 2) blocks (possibly of a smaller size)
to maintain the FAT.


Do you or anyone else know of such a module available in open source?

If not then I shall have to write one.  Cue Red Hat to tell me about what
they would like to see me provide :-)

Andy


> -----Original Message-----
> From: Andrew Lunn [ mailto:andrew.lunn@ascom.ch ]
> Sent: 03 September 2001 09:34
> To: Simpkins, Andy
> Cc: eCos-Discuss (E-mail)
> Subject: Re: [ECOS] FLASH file system
> 
> 
> On Mon, Sep 03, 2001 at 09:25:45AM +0100, Simpkins, Andy wrote:
> > Hi there,
> > 
> > Does anyone know if there is an eCos FLASH file handling 
> module (i.e. treats
> > FLASH as a disk)
> 
> The ROM FS can run this the FS in FLASH. Its read only. Is 
> that what you mean?
> 
> Or do you mean using the flash as a block device? You open /dev/flash
> and read blocks and write blocks? Im not sure that would be very
> efficient. The flash on my device has 256k blocks.
> 
>         Andrew
> 

RE: [ECOS] FLASH file system

[Gustav Kälvesten]

Hi,

>the original writer of JFFS2, David Woodhouse is now with Cygnus /
>RedHat in Cambridge. His view on porting to eCos was that seperating
>form vfs would be the main challenge. I'm currently having a look at
>this, and I'll probably just pull out the key functionality to put into
>the eCos filesystem framework.
>
>JFFS2 source at http://www.linux-mtd.infradead.org/
>David's paper on JFFS2 at  http://www.infradead.org/~dwmw2/jffs2.pdf .
>
>Dominic

What is the status of this effort?

with kind regards
Gustav Kalvesten

RE: [ECOS] FLASH file system

[Dominic Ostrowski]

Hi Andy,

the original writer of JFFS2, David Woodhouse is now with Cygnus /
RedHat in Cambridge. His view on porting to eCos was that seperating
form vfs would be the main challenge. I'm currently having a look at
this, and I'll probably just pull out the key functionality to put into
the eCos filesystem framework.

JFFS2 source at http://www.linux-mtd.infradead.org/
David's paper on JFFS2 at  http://www.infradead.org/~dwmw2/jffs2.pdf .

Dominic

RE: [ECOS] FLASH file system

[Simpkins, Andy]

On the surface it looks like JFFS2 is just what I am looking for...

Can someone point me in the direction for JFFS2 documentation and source?
All I can find is the red hat announcement on the device and the a build for
use with the 'familiar platform' ipaq.

that should enable me to determine if this is the right thing for me to
pursue.

Has anyone (or is anyone in the process of) ported JFFS2 to eCos.
again the red hat announcement indicated that a port was soon to follow the
Linux release...


Andy

> -----Original Message-----
> From: Simpkins, Andy 
> Sent: 03 September 2001 10:18
> To: 'Andrew Lunn'; Simpkins, Andy
> Cc: eCos-Discuss (E-mail)
> Subject: RE: [ECOS] FLASH file system
> 
> 
> Andrew,
> 
> What I am looking for is something like the following...
> 
> - Ability to read and write files to FLASH
> - Because BLOCK size in flash is typically quite large (>64K) 
> then it is desirable to split blocks into sub-blocks of a 
> more reasonable size.  
> - This now leaves the problem of erasing (as the smallest 
> erase size is 1 block).
> - By leaving 1 Block free space in the file system at all 
> times it is possible to 'juggle' data around (i.e. 
> defragmenter) such that sub-blocks no-longer in use may be 
> freed up for re-use.
> - Obviously this will require 1 (or 2) blocks (possibly of a 
> smaller size) to maintain the FAT.
> 
> 
> Do you or anyone else know of such a module available in open source?
> 
> If not then I shall have to write one.  Cue Red Hat to tell 
> me about what they would like to see me provide :-)
> 
> Andy
> 
> 
> > -----Original Message-----
> > From: Andrew Lunn [ mailto:andrew.lunn@ascom.ch ]
> > Sent: 03 September 2001 09:34
> > To: Simpkins, Andy
> > Cc: eCos-Discuss (E-mail)
> > Subject: Re: [ECOS] FLASH file system
> > 
> > 
> > On Mon, Sep 03, 2001 at 09:25:45AM +0100, Simpkins, Andy wrote:
> > > Hi there,
> > > 
> > > Does anyone know if there is an eCos FLASH file handling 
> > module (i.e. treats
> > > FLASH as a disk)
> > 
> > The ROM FS can run this the FS in FLASH. Its read only. Is 
> > that what you mean?
> > 
> > Or do you mean using the flash as a block device? You open 
> /dev/flash
> > and read blocks and write blocks? Im not sure that would be very
> > efficient. The flash on my device has 256k blocks.
> > 
> >         Andrew
> > 
> 

Re: [ECOS] FLASH file system

[Andrew Lunn]

On Mon, Sep 03, 2001 at 09:25:45AM +0100, Simpkins, Andy wrote:
> Hi there,
> 
> Does anyone know if there is an eCos FLASH file handling module (i.e. treats
> FLASH as a disk)

The ROM FS can run this the FS in FLASH. Its read only. Is that what you mean?

Or do you mean using the flash as a block device? You open /dev/flash
and read blocks and write blocks? Im not sure that would be very
efficient. The flash on my device has 256k blocks.

        Andrew

[ECOS] FLASH file system

[Simpkins, Andy]

Hi there,

Does anyone know if there is an eCos FLASH file handling module (i.e. treats
FLASH as a disk)

If so can you point me in the right direction...

Many thanks

Andy

Re: [ECOS] Flash file system

[james chen]

        I have looked the source code of JFFS2, but it is based on linux's
VFS. Now I want to port it to eCos, I don't know how to start it, does I
need port VFS+JFFS2 to eCos or only need to JFFS2 to eCos? any suggestion is
welcom!

Best Regards,
james


----- Original Message -----
From: Jonathan Larmour <jlarmour@redhat.com>
To: james chen <james_ch1@sina.com>
Cc: <ecos-discuss@sources.redhat.com>
Sent: Saturday, May 19, 2001 3:23 AM
Subject: Re: [ECOS] Flash file system


> james chen wrote:
> >
> > Hi,
> >      Has anyone ported JFFS(Journaling Flash File System, developed by
Axis
> > Communications AB in Sweden) to eCos?
>
> No, and it's not very likely because it's GPL'd and has been superseded by
> JFFS2. Porting _that_ sounds much more interesting, but we have no plans
to
> do that right now. Of course if anyone contributed it, or contracted Red
> Hat to do it, that would do it :-).
>
> <gratuitous advert>
> If people are considering new ports, extensions, customizations, or
> improvements to eCos or RedBoot, and would be interested in Red Hat
helping
> them do this, just e-mail ecos-info@redhat.com to discuss it further.
> </gratuitous advert>
>
> Jifl
> --
> Red Hat, Rustat House, Clifton Road, Cambridge, UK. Tel: +44 (1223) 271062
> Maybe this world is another planet's Hell -Aldous Huxley || Opinions==mine
>
>

Re: [ECOS] Flash file system

[Jonathan Larmour]

james chen wrote:
> 
> Hi,
>      Has anyone ported JFFS(Journaling Flash File System, developed by Axis
> Communications AB in Sweden) to eCos?

No, and it's not very likely because it's GPL'd and has been superseded by
JFFS2. Porting _that_ sounds much more interesting, but we have no plans to
do that right now. Of course if anyone contributed it, or contracted Red
Hat to do it, that would do it :-).

<gratuitous advert> 
If people are considering new ports, extensions, customizations, or
improvements to eCos or RedBoot, and would be interested in Red Hat helping
them do this, just e-mail ecos-info@redhat.com to discuss it further.
</gratuitous advert>

Jifl
-- 
Red Hat, Rustat House, Clifton Road, Cambridge, UK. Tel: +44 (1223) 271062
Maybe this world is another planet's Hell -Aldous Huxley || Opinions==mine

[ECOS] Flash file system

[james chen]

Hi,
     Has anyone ported JFFS(Journaling Flash File System, developed by Axis
Communications AB in Sweden) to eCos?
Best Regards,
James