Well Known ioctl Interfaces

Many ioctl(9E) operations are common to a class of device drivers. For example, most disk drivers implement many of the dkio(7I) family of ioctls. Many of these interfaces copy in or copy out data structures from the kernel, and some of these data structures have changed size in the LP64 data model. The following section lists the ioctlsthat now require explicit conversion in 64-bit driver ioctl routines for the dkio, fdio(7I), fbio(7I), cdio(7I), and mtio(7I) families of ioctls.

ioctl command	Affected data structure	Reference
DKIOCGAPART DKIOCSAPART	dk_map dk_allmap	dkio(7I)
DKIOGVTOC DKIOSVTOC	partition vtoc	dkio(7I)
FBIOPUTCMAP FBIOGETCMAP	fbcmap	fbio(7I)
FBIOPUTCMAPI FBIOGETCMAPI	fbcmap_i	fbio(7I)
FBIOCCURSOR FBIOSCURSOR	fbcursor	fbio(7I)
CDROMREADMODE1 CDROMREADMODE2	cdrom_read	cdio(7I)
CDROMCDDA	cdrom_cdda	cdio(7I)
CDROMCDXA	cdrom_cdxa	cdio(7I)
CDROMSUBCODE	cdrom_subcode	cdio(7I)
FDIOCMD	fd_cmd	fdio(7I)
FDRAW	fd_raw	fdio(7I)
MTIOCTOP	mtop	mtio(7I)
MTIOCGET	mtget	mtio(7I)
MTIOCGETDRIVETYPE	mtdrivetype_request	mtio(7I)
USCSICMD	uscsi_cmd	scsi_free_consistent_buf(9F)

Device Sizes

The nblocks property is exported by each slice of a block device driver. This property contains the number of 512-byte blocks that each slice of the device can support. The nblocks property is defined as a signed 32-bit quantity, which limits the maximum size of a slice to 1 Tbyte.

Disk devices that provide more than 1 Tbyte of storage per disk must define the Nblocks property, which should still contain the number of 512 byte blocks that the device can support. However, Nblocks is a signed 64-bit quantity, which removes any practical limit on disk space.

The nblocks property is now deprecated. All disk devices should provide the Nblocks property.