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undeadly honked 14 Nov 2025 12:00 +0100

Transition to support for 52 partitions

In -current, Theo de Raadt (deraadt@) has started the transition to support for 52 disk partitions (on a subset of hardware architectures):

CVSROOT:	/cvs
Module name:	src
Changes by:	deraadt@cvs.openbsd.org	2025/11/13 13:59:14

Modified files:
	sys/dev/ata    : wd.c 
	sys/kern       : kern_pledge.c 
	sys/sys        : disklabel.h dkio.h 
	sys/scsi       : sd.c 
	sys/dev/isa    : fdreg.h 
	sys/arch/sparc64/dev: fd.c 

Log message:
Begin transition to 52-partition support.  The partition encoding used
to be lowest 4 bits of dev_t, and now becomes 6.  This supplies 64
partitions in struct disklabel.d_partitions[MAXPARTITIONSUNIT], but we
only use 52 of these slots (an architecture can be either 16 partition
or 52 partition, depending on MD define MAXPARTITIONS).  The
52-partition limit is due to single-character representation limit of
a-zA-Z.  We supply a backwards-compat ioctl for a while which can read
an disklabel structure.

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