From: Paul Guyot (pguyot_at_kallisys.net)
Date: Thu May 13 2004 - 22:23:28 PDT
Aux environs du 13/05/04 à 22:24 -0500, sous le titre "Re: [NTLK]
Reading PC format... a theory...", Jeff Sheldon prit sa plus belle
plume pour écrire les mots suivants:
>On Thu, May 13, 2004 at 10:12:19PM +0200, Doug Augustyn wrote:
>> Please note that this will only work if both cards are of the same
>> capacity, if you try it with two different sized cards and it works,
>> please tell me.
>
>You can copy data from, say, a 16Mb card to a 32Mb card, but the data
>footprint will still be identified as 16Mb. If you hexdump the dd'ed
>image of a freshly NewtOS formatted card after trying out various
>partition schemes, you'll be able to get an extremely rough idea of how
>the partitioning is handled by way of Paul Guyot's ATA driver.
Actually, I did document this partitioning format at some point and I
don't think it did change since. Growing a partition isn't very
difficult either.
I knew it was somewhere on the web:
http://www.kallisys.com/files/newton/ATA/Newton-Stores-Collection-Format.txt
http://www.kallisys.com/files/newton/ATA/Paged-Stores-Format.txt
I don't know how accurate this is, make sure you do backups before
trying this. Also make sure you test the version is the one
documented. There may be a new store format soon.
Growing a partition means:
1- increasing its size in the header sector (or superblock in
traditional file system terminology)
2- add new map sectors at the end (map sectors are a simple linked
list), as much as necessary
You can even move partitions. I think that all IDs except in the
partition map are relative to the beginning of the store.
The problem with this format is that:
- one cannot list all the objects the system has recorded
- it costs a lot when a transaction is aborted (I stupidly supposed
it didn't happen often, but everytime you find ATA Support is slow,
it's happening, like installing packages)
- it doesn't allow (and ATA Support doesn't) batch reads.
Paul
-- Philosophie de baignoire - consultations sur rendez-vous. NPDS/NewtonOS: http://newton.kallisys.net:8080/ Apache/FreeBSD: http://www.kallisys.com/ -- This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries Official Newton FAQ: http://www.chuma.org/newton/faq/ WikiWikiNewt for all kinds of articles: http://tools.unna.org/wikiwikinewt/
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