Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[Martin Langhoff]

On Fri, Nov 13, 2009 at 9:55 AM, Martin Langhoff
 wrote:
> We do have an internal format - the ._metadata.json format outlined
> for the JEBs themselves. Sugar 0.82 writes that out in the internal
> 'datastore' storage. We can reuse it here.

Ok - so last Friday Bert Desmet and I explored the relevant code in
Sugar and started drafting out a patch.

This is draft and incomplete - but I think it shows the direction in
which I am looking
http://dev.laptop.org/attachment/ticket/9657/0001-journal.model.copy-write-json-formatted-metadata.patch

In the patch, I also separated the preview off, so for example if you
have a turtleart 'Foo' Journal Entry, then we save

 - Foo.gtar
 - .Foo.metadata
 - .Foo.preview

Reading base64 enc stuff in the middle of JSON hurts my eyes -- but
maybe I should just keep the preview embedded in there to simplify.

However it is we store it, we have to handle these cases:

 - copy from datastore to ext storage -- what the patch above does
 - rename in ext storage (which I think also has other issues -- ie:
renames don't work )
 - delete in ext storage
 - read the metadata [if available] when mounting the USB stick

cheers,


m
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 martin.langh...@gmail.com
 mar...@laptop.org -- School Server Architect
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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[Martin Langhoff]

On Fri, Nov 13, 2009 at 1:33 AM, K. K. Subramaniam  wrote:
> Keeping meta-data in the same directory (folder) is the way to go. Of course,
> the meta-data has to be a hidden file.

Of course - why?

> FWIW, www.freedesktop.org contains a bunch of  "standards" (really
> conventions) for handling meta-data.

Not worth much it turns out -- for they have no mention of metadata
_storage_ in any of the specs.

We do have an internal format - the ._metadata.json format outlined
for the JEBs themselves. Sugar 0.82 writes that out in the internal
'datastore' storage. We can reuse it here.

cheers,



m
-- 
 martin.langh...@gmail.com
 mar...@laptop.org -- School Server Architect
 - ask interesting questions
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 - http://wiki.laptop.org/go/User:Martinlanghoff
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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[K. K. Subramaniam]

On Thursday 12 November 2009 08:36:58 pm Bert Freudenberg wrote:
> IMHO separating the meta-data from the file itself is a good idea. Having
>  one database at the root of the stick is just too fragile. Better store
>  meta data next to the file in question, like myimage.jpg and
>  myimage.journalentry?
Keeping meta-data in the same directory (folder) is the way to go. Of course, 
the meta-data has to be a hidden file.

FWIW, www.freedesktop.org contains a bunch of  "standards" (really 
conventions) for handling meta-data.

Subbu
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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[Hal Murray]

martin.langh...@gmail.com said:
> In terms of use cases, saving to a USB disk allows for personal
> backups -- like before a complete upgrade / reflash, which is still
> used in many cases.

> You wouldn't use a system that didn't let you copy your files to a
> disk, would you? 

How old do kids have to be before they understand the ideas of backup?  How 
about making copies?  (to give to others and as a snapshop to keep for 
yourself)

There are many reasons for wanting a backup.
hardware errors
  including the hardware getting lost or stolen
software errors
operator errors
user errors

The backup mechanism is primarily making a copy of the data.  That mechanism 
can also be used for other things:
transferring data to somebody else
  giving a paper to your teacher
taking a snapshot at interesting times
  saving a copy of a paper exactly as you gave it to your teacher

Tangled up in here is transferring data to other software and/or other 
hardware platforms.  If your system uses proprietary file formats you need a 
way to translate the information into a format that other people can use.  
Same for uncommon hardware.


I think whatever backup/copy mechanism OLPC/Sugar ends up with should be 
convenient for all of those tasks.  (and probably a few others I haven't 
thought of)



-- 
These are my opinions, not necessarily my employer's.  I hate spam.



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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[Martin Langhoff]

On Thu, Nov 12, 2009 at 6:16 PM, David Van Assche  wrote:
> and storing images in Base64 for example?

Ugh! Why - for ASCII art enjoyment?



m
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 martin.langh...@gmail.com
 mar...@laptop.org -- School Server Architect
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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[David Van Assche]

and storing images in Base64 for example?

David

On Thu, Nov 12, 2009 at 4:12 PM, Martin Langhoff
wrote:

> On Thu, Nov 12, 2009 at 4:06 PM, Bert Freudenberg 
> wrote:
> > IMHO separating the meta-data from the file itself is a good idea. Having
> one database at the root of the stick is just too fragile. Better store meta
> data next to the file in question, like myimage.jpg and
> myimage.journalentry?
>
> Good point, and the solution you suggest seems good to me too.
>
> Unless Sugar has another mechanism already that "should" be kicking
> in, and for some reason is not working...?
>
>
>
> m
> --
>  martin.langh...@gmail.com
>  mar...@laptop.org -- School Server Architect
>  - ask interesting questions
>  - don't get distracted with shiny stuff  - working code first
>  - http://wiki.laptop.org/go/User:Martinlanghoff
> ___
> Sugar-devel mailing list
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> http://lists.sugarlabs.org/listinfo/sugar-devel
>



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Ebner-Eschenbach
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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[Martin Langhoff]

On Thu, Nov 12, 2009 at 4:06 PM, Bert Freudenberg  wrote:
> IMHO separating the meta-data from the file itself is a good idea. Having one 
> database at the root of the stick is just too fragile. Better store meta data 
> next to the file in question, like myimage.jpg and myimage.journalentry?

Good point, and the solution you suggest seems good to me too.

Unless Sugar has another mechanism already that "should" be kicking
in, and for some reason is not working...?



m
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 martin.langh...@gmail.com
 mar...@laptop.org -- School Server Architect
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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[Bert Freudenberg]

On 12.11.2009, at 14:08, Martin Langhoff wrote:

> Not kidding, at least one of the bugs listed in SL's tracker about
> Journal Entry sharing would be fixed with the JEB-based approach I am
> proposing. And once the Journal can prepare a JEB, you just write it
> to the USB disk mountpoint.

But (IIUC what JEB means) that would not cover the use case of wanting to put 
e.g. a JPEG image on the USB to view it on a non-Sugar machine.

IMHO separating the meta-data from the file itself is a good idea. Having one 
database at the root of the stick is just too fragile. Better store meta data 
next to the file in question, like myimage.jpg and myimage.journalentry?

- Bert -


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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[David Van Assche]

its true its an unecessary step in THIS particular scenario, but I'm thiking
more of a universal tool we could rely on for our datar storage, and
something like xmpp file sotrage XEP came to mind. IT contains
rudeimentary autehntication, file storage per person or for mutiple people
(ie a group like scenario) and probably fits via the d tube or x tube
scenario

I'm just saying that if we choose to use xmpp via technology as its main
communicatinos framework we should really nmaximmize its usage. There is so
much undiscovered potential there, so many possible ways of doing even the
simplest of person to person communictaion, persence and sharing. I was not
at ll suggesting that someone replace using USB base data sharing, but
exploring ways in which in on exmple, u could open a dtube with telepathy
between the 2 mechanisms, lets call them usb sticks for now, and transfer
that way, set  presence state, avtar, and any ohter cool sutff xmpp can
do...

I'm jus saying should we be exploring it?

Daivd

On Thu, Nov 12, 2009 at 2:08 PM, Martin Langhoff
wrote:

> On Thu, Nov 12, 2009 at 1:55 PM, David Van Assche 
> wrote:
> > inclydiung usb if that was desired
>
> Maybe your usb disk has a firmware smart enough to run telepathy :-)
>
> Not kidding, at least one of the bugs listed in SL's tracker about
> Journal Entry sharing would be fixed with the JEB-based approach I am
> proposing. And once the Journal can prepare a JEB, you just write it
> to the USB disk mountpoint.
>
> Telepathy in the middle is overengineering a bridge to get from the
> kitchen to the bedroom. I am happy to walk.
>
> In terms of use cases, saving to a USB disk allows for personal
> backups -- like before a complete upgrade / reflash, which is still
> used in many cases.
>
> You wouldn't use a system that didn't let you copy your files to a
> disk, would you?
>
>
>
> m
> --
>  martin.langh...@gmail.com
>  mar...@laptop.org -- School Server Architect
>  - ask interesting questions
>  - don't get distracted with shiny stuff  - working code first
>  - http://wiki.laptop.org/go/User:Martinlanghoff
>



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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[Martin Langhoff]

On Thu, Nov 12, 2009 at 1:55 PM, David Van Assche  wrote:
> inclydiung usb if that was desired

Maybe your usb disk has a firmware smart enough to run telepathy :-)

Not kidding, at least one of the bugs listed in SL's tracker about
Journal Entry sharing would be fixed with the JEB-based approach I am
proposing. And once the Journal can prepare a JEB, you just write it
to the USB disk mountpoint.

Telepathy in the middle is overengineering a bridge to get from the
kitchen to the bedroom. I am happy to walk.

In terms of use cases, saving to a USB disk allows for personal
backups -- like before a complete upgrade / reflash, which is still
used in many cases.

You wouldn't use a system that didn't let you copy your files to a
disk, would you?



m
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 martin.langh...@gmail.com
 mar...@laptop.org -- School Server Architect
 - ask interesting questions
 - don't get distracted with shiny stuff  - working code first
 - http://wiki.laptop.org/go/User:Martinlanghoff
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Re: [Sugar-devel] User workflow sharing "Journal Entries" over USB sticks

[David Van Assche]

This all sounds like a great current solutinon, but shouldn't we be looking
at more long term network ubquity solutions. It seems to be that having a
telepathy backend and frontend would allow us to share files anty which wat
inclydiung usb if that was desired. From my experience in schools, though
they seem like god's gift at the beginning of the semester, teachers end up
cursing the the things left right and center, through no fault of usb, but
that of human error, where people forget/loose/haver them eaten by their
pets, truly)

sorry so to sounds so pessimisitc today, mybe fell out of the wrong side of
the bed,
David

On Thu, Nov 12, 2009 at 12:57 PM, Martin Langhoff  wrote:

> On Thu, Nov 12, 2009 at 12:44 PM, Martin Langhoff
>  wrote:
> > Filed it as http://dev.laptop.org/ticket/9657 - can't find anything on
>
> And also related: http://dev.laptop.org/ticket/9658 about the
> impossibility of exchanging data between Sugar versions 0.82 and 0.84
>
> This is rather awkward -- users cannot save their own files to a USB
> stick (pre upgrade) and expect them to work once upgraded.
>
> I don't expect all deployments will use olpc-update :-/
>
>
>
> m
> --
>  martin.langh...@gmail.com
>  mar...@laptop.org -- School Server Architect
>  - ask interesting questions
>  - don't get distracted with shiny stuff  - working code first
>  - http://wiki.laptop.org/go/User:Martinlanghoff
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>



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