From: Bernd Sieker...

>> You have written "blocks". Thus if the blocksize (aka fs fragment size?) is
>> e.g. 1024 bytes - then NetBSD can access 4*(1024^4) i.e. 4096GB. Right?

>No, the BSD ffs has blocks and frags, which are different. Typical block
>size is 8k, frag size 512 bytes, but different values can be chosen
>when 'newfs'ing.

>I hope I'm making sense.

Yes. You are. Thought the default "frag" was 1024 bytes for some time though.

>> 
>> Understood. I can do it this way: 'root' - within the limits. 'swap' and
>'usr'
>> above. But this applies only if one wants to boot NetBSD from the bootblock
>I
>> suppose? Otherwise all can be placed above AFAI understand.

>Yes, but using AmigaOS partitions above the limit is still not advisable,
>since, as Ignatios pointed out, there are almost half a dozen half-cooked
>ways of doing that.


Alright. I understand. Now as I know that it should work, I would like to ask
the last question or rather come back to the one I started with: What are the
_exact_ limits for the AmigaOS access?

I want to know the exact limits because I don't want to set-aside 200 or 300
MB's of the drive's space just because I don't know where to set the border
between AmigaOS accessible part of the drive and the NetBSD accessible one.

Knowing exactly the limits would allow me to do optimal partitioning and this
is the point why I bother all of you with my questions.

This would also help other NetBSD users and could (IMHO) eventually be placed
in NetBSD's docs and faqs.

**********************************************


From: Ignatios Souvatzis...

[...]

>Uhm, you need to create the NetBSD partitions using hdtoolbox or something 
>similar. You can use hdtoolbox if you have the newwhatwasit patches from 
>Amiga Int.

The simple partitioning seems to be no problem for the old hdtoolbox. At least
I experienced no probs with several drives >4GB. It is just that up till now
I've always left everything above 3950MBs unused. On the other hand I also
temporarily created some partitions above the 4G but haven't used them since I
thought it may wrap-up the counters and overwrite the beginning of the drive
or do other bizarre things...

 
>>>Other than that, your root partition must be below 4GB, so that the ROM can
>>>access the bootblock, and the kernel on behalf of the bootblock.
 
>> Understood. I can do it this way: 'root' - within the limits. 'swap' and
>> 'usr' above. But this applies only if one wants to boot NetBSD from the 
>> bootblock I suppose? Otherwise all can be placed above AFAI understand.

>right. But why not reserve 50 MB below, and be able to choose the OS from 
>the Amiga boot menu? (thats 50 of 4096... not an unreasonable number.)

Yes! As I've written "'root' - within the limits." It is not unreasonable.
Just where the limits exatly are? What HDD block is the last accessible one?
Is it the IORequest limit you've written about? Or is there something else? I
think that IORequest should not be responsible for the *.device's job of
accessing the proper (or improper) blocks on the drive.


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