[Info-vax] questions on initialize/gpt

[Simon Clubley]

On 2015-06-21, Dirk Munk <munk at home.nl> wrote:
> I just read the chapter on the DCL initialize command, and there it says:
>
> >> When /GPT is specified, the system file [000000]GPT.SYS is created. 
> GPT.SYS contains partition/boot information needed by the IA64 console 
> software. (GPT is an abbreviation for GUID Partition Table, where GUID 
> stands for Global Unique Identifier.) <<
>
> That seems to suggest the disk gets a industry standard GUID Partition 
> Table, or not?
>
> But then you would expect to be able to take a partition on an existing 
>   disk with a GPT label, and format it with ODS-2 or ODS-5, but I can't 
> find any information on that.
>
> What is going on here?

AIUI, (not actually having used IA-64 VMS) the GPT.SYS file is just
a fake partition created by VMS $ init to allow the contents to be
visible from the console.

As such (since VMS doesn't support partitions) this means $ init has
to do the whole thing and can't use any existing structures because
it needs to create the fake partition once it knows where the space
for the fake partition has been allocated within the ODS-2/ODS-5
volume.

The alternative would be for $ init to have code added to merge the
existing partition into the newly allocated VMS ODS-2/ODS-5 structures
during $ init. I imagine that's a lot more complicated than just
creating a fake partition within the new ODS-2/ODS-5 volume.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
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