[openbeosstorage] Re: Amiga RDB

On Mon, 09 Jun 2003 19:35:52 +0200 CEST "Axel Dörfler" <axeld@pinc-
software.de> wrote:
> "Ingo Weinhold" <bonefish@xxxxxxxxxxxxxxx> wrote:
> > > > Now, balancing the arguments I tend to like 1) most. I would 
> > > > perhaps revise this judgement, if Axel told us, that the 
> > > > reserved 
> > > > space stuff
> > > > is indeed used in practice and the size of the reserved space 
> > > > is
> > > > usually rather large (like dozens of MBs, which I strongly 
> > > > doubt). 
> > > > Then I would favor 3), for I really don't like 2). Sorry Tyler, 
> > > > I 
> > > > can't 
> > > > get to like the virtual partitions.
> > > Yes, I think I currently like 1) best as well. Otherwise, I can 
> > > just 
> > > as 
> > > easily handle 2) or 3), and since 2) has not gone over very well 
> > > at 
> > > all, I would go for 3) as well. :-)
> > OK, it seems we could all live rather well with 1) (unless Axel 
> > vetos). 
> > So, let's go for it.
> 
> I finally got around checking it out, and I have to partially veto:
> a) that feature is used,
> b) but it seems always to be used in the same way
> 
> All my partitions have 2 reserved blocks at the beginning, and zero 
> at 
> the end. I guess those two blocks are generally reserved by the drive 
> setup application for some kind of boot loader, but I am not sure 
> (but 
> it looks like it).
> Furthermore, the first longword of an Amiga FS (in that reserved 
> region) seems to be file system ID as specified in the partition 
> structure - but it doesn't have to be; the linux file systems even 
> seem 
> to use that space... (but it could also contain just garbage in this 
> case).
> I am not yet sure how to handle the real partition size - I'll have a 
> deeper look at Amiga FFS though, and then I might know. Right now, I 
> would think that it's best to simply let the file system decide what 
> to 
> do with this extra space; at least it looks like the contents differ 
> on 
> different file systems - that means, that the partition would span 
> the 
> whole space including the reserved areas.
> I would just be nice if the file system could access the space 
> information, though.

Mmh, we have rather few options: We publish a device for the partition 
that either includes the reserved space or that doesn't. Unless I miss 
something, Linux has exactly the same options for its /dev/hdaN. If 
your observation is correct, then those partitions include the reserved 
part. I find this not nice, because that means, the file systems must 
be aware of the underlying partitioning system. Not that this was a 
problem for us...

CU, Ingo

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