found inside extended partitions and used to create logical partitions.
At this time write/modify support is not (yet) present.
The EBR and MBR schemes both check the parent scheme. The MBR will
back-off when nested under another MBR, whereas the EBR only nests
under a MBR.
the method for the (indent == NULL) case (i.e. the kern.geom.conftxt
sysctl). The purpose is to extend the conftxt output with scheme-
specific fields which can be used by libdisk. In particular, have
the schemes dump the xs and xt fields, which contain the backward
compatible values for class type and partition type. This allows
libdisk to work with the legacy slicers as well as with gpart and
helps/promotes migration.
to declaring a proper module. The module event handler is part of the
gpart core and will add the scheme to an internal list on module load
and will remove the scheme from the internal list on module unload.
This makes it possible to dynamically load and unload partitioning
schemes.
partition table is empty, check to see if we have something that
looks sufficiently like a BPB. On non-i386 machines, the boot
sector typically doesn't contain boot code; the end of the boot
sector is all zeroes. This is also where the partition table is
for MBRs.
We only check the sector size and cluster size, as that seems to
be the most reliable across implementations, BPB versions and
platforms.
only because there's a partition table where the boot sector has
boot code. Boot sectors without boot code look like a MBR for all
practical purposes. This change adds a check for the partition table
and fails the probe when it's obvously invalid. The assumption being
that the sector contains a boot sector and not a MBR.
More checks are needed to distinguish a boot secto without boot code
from a (empty) MBR.
don't have it. Some partitioning schemes, as well as file systems,
operate on the geometry and without it such schemes (e.g. MBR)
and file systems (e.g. FAT) can't be created. This is useful for
memory disks.
