NAME

cmdk − common disk driver

AVAILABILITY

x86

DESCRIPTION

The cmdk device driver is a common interface to various disk devices.  The driver supports magnetic fixed disks, magnetic removable disks, and both 512-byte and 2K-byte CD-ROM drives. 

The block-files access the disk using the system’s normal buffering  mechanism and are read and written without regard to physical disk records.  There is also a "raw" interface that provides for direct transmission between the disk and the user’s read or write buffer.  A single read or write call usually results in one I/O operation; raw I/O is therefore considerably more efficient when many bytes are transmitted.  The names of the block files are found in /dev/dsk; the names of the raw files are found in /dev/rdsk. 

I/O requests to the magnetic disk must have an offset and transfer length that is a multiple of 512 bytes or the driver returns an EINVAL error.  However, I/O requests to the 2K-byte CD-ROM drive must be a multiple of 2K bytes. Otherwise, the driver returns an EINVAL error, too. 

Slice 0 is normally used for the root file system on a disk, slice 1 as a paging area (for example, swap), and slice 2 for backing up the entire Solaris fdisk partition.  Other slices may be used for usr file systems or system reserved area. 

Fdisk partition 0 is to access the entire disk and is generally used by the fdisk(1M) ­program. 

FILES

/dev/dsk/cntndn[s|p]n block device (SCSI)

/dev/dsk/cndn[s|p]n block device (IDE)

/dev/rdsk/cntndn[s|p]n
raw device (SCSI)

/dev/rdsk/cndn[s|p]n raw device (IDE) where:

SEE ALSO

fdisk(1M), mount(1M), lseek(2), read(2), write(2), directory(3C), vfstab(4), dkio(7I)

SunOS 5.5/x86  —  Last change: 20 Jul 1994