GPT as default?

Marcel Moolenaar xcllnt at
Sun Apr 22 02:03:51 UTC 2007

On Apr 21, 2007, at 5:40 PM, Ivan Voras wrote:

> Marcel Moolenaar wrote:
>> On Apr 21, 2007, at 12:53 AM, Scott Long wrote:
>>> And as much as it pains me to say it, DES is right here ;-)   
>>> geom_gpt
>>> needs to implement the appropriate verbs to allow apps to  
>>> instruct the
>>> gpt instance to modify itself, instead of forcing apps to blindly
>>> overwrite it.
>> Those verbs exist. There's no poor design  There's only a long time
>> to get from A to B.
> In particular, what is missing?

A (generic) tool that utilizes the verbs.

> Users will need at least the possibility to add and remove partitions
> while the system is running and some partitions are mounted.  
> Looking at
> the source tree, it seems that the userland utility is missing?  
> (There's
> gpt(8) but it's for the old geom_gpt, right?)

gpt(8) does not use GEOM verbs. It was written before that time.
That's what the complains are mostly about.

I started to convert geom_gpt to use verbs, but that grew into
g_part because it's not only GPT that needs verbs and I also saw
that APM (The Apple partitioning scheme) needed to be supported,
which, if I were to do that, would need exactly the same thing.
So, I extended the scope of the work...

> Subquestion: geom_gpt names partitions "xxxp0", "xxxp1", etc. so what
> happens if one of them is deleted? Will the numbers shift on next  
> boot?

No. The partition number is the index of the partition entry in the  
That typically does not change (though nothing prevents a tool to  
the entries in the table or compact the table).

> I think I'l also include out of the box geom_label support :)

GPT (like APM) has labels, which we should propagate. It's not a
priority for me, but I presume that it shouldn't be too difficult
to interface with geom_label.

> Alternative is to use GUIDs, like some Linuxes do, so we have entries
> like /dev/gpt/38a52be4-9352-453e-af97-5c3b448652f0

I've thought about that too, but again it's not a priority. It takes
me long enough as it is to adopt the new world order that other
features have to wait :-)

Marcel Moolenaar
xcllnt at

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