Haai,

Considering both the limitation of 16 partitions per disklabel (which is
enough for most applications, and thus I believe would be unwise to
increase) and the fancy footwork that still seems to be required to have
multiple slices of NetBSD disklabels to coexist peacefully on the same
drive, I propose adding the following mechanisms to aid in the usage of
recursive partitioning:

1) Adding filesystem type 24 as 'Recursive' and claiming MBR partition
type 172 as 'UNIX recursive' (since it could also be useful for other
Unices);
2) Creating an /etc/vndtab with the fields 'source file', 'preferred
target device' ('*' == any, '?' == any single-number), 'type', 'options';
2a) Aside from the already existing options of vnconfig, add a 'fail on
unvailability of preferred target' option or something similar;
3) Call the new 'vnconfig -a' before mounting non-root partitions.

It would be preferable to make the number of available vnds dynamic, using
sysctl(8) to change it.

This has several advantages:

1) Root partitions can be stored in the primary disklabel, allowing direct
access;
2) Swap space in the primary disklabel can be shared (could cause problems
with savecore(8) and switching OSes directly after panic?);
3) This doesn't enforce the increase of the disklabel size for everyone.

Comments?

BTW, I propose reserving FS type 25 for UDF, since we already have one for
ISO 9660, as well.

Baai,

De Zeurkous
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Friggin' Machines!