sd

SD(4)			  Linux Programmer’s Manual			SD(4)



NAME
       sd - Driver for SCSI Disk Drives

SYNOPSIS
       #include	  <linux/hdreg.h>	   /*  for  HDIO_GETGEO	 */  #include
       <linux/fs.h>	      /* for BLKGETSIZE and BLKRRPART */

CONFIG
       The block device name has the following form: sdlp, where l is a	 let-
       ter denoting the physical drive, and p is a number denoting the parti-
       tion on that physical drive.  Often, the partition number, p, will  be
       left off when the device corresponds to the whole drive.

       SCSI  disks have a major device number of 8, and a minor device number
       of the form (16 * drive_number) + partition_number, where drive_number
       is  the number of the physical drive in order of detection, and parti-
       tion_number is as follows:

       partition 0 is the whole drive
       partitions 1-4 are the DOS "primary" partitions
       partitions 5-8 are the DOS "extended" (or "logical") partitions

       For example, /dev/sda will have major 8, minor 0, and  will  refer  to
       all  of	the  first  SCSI drive in the system; and /dev/sdb3 will have
       major 8, minor 19, and will refer to the third DOS "primary" partition
       on the second SCSI drive in the system.

       At  this	 time, only block devices are provided.	 Raw devices have not
       yet been implemented.

DESCRIPTION
       The following ioctls are provided:

       HDIO_GETGEO
	      Returns the BIOS disk parameters in the following structure:
		     struct hd_geometry {
			   unsigned char heads;
			   unsigned char sectors;
			   unsigned short cylinders;
			   unsigned long start;
		     };

	      A pointer to this structure is passed as the  ioctl(2)  parame-
	      ter.

	      The  information returned in the parameter is the disk geometry
	      of the drive as understood by DOS!  This geometry	 is  not  the
	      physical	geometry  of the drive.	 It is used when constructing
	      the drive’s partition table, however, and is needed for  conve-
	      nient  operation	of  fdisk(1), efdisk(1), and lilo(1).  If the
	      geometry information is not available, zero  will	 be  returned
	      for all of the parameters.

       BLKGETSIZE
	      Returns  the  device  size  in sectors.  The ioctl(2) parameter
	      should be a pointer to a long.

       BLKRRPART
	      Forces a re-read of the SCSI disk partition tables.  No parame-
	      ter is needed.

	      The  scsi(4)  ioctls  are	 also  supported.   If	the  ioctl(2)
	      parameter is required, and it is NULL, then ioctl() will return
	      -EINVAL.

FILES
       /dev/sd[a-h]: the whole device
       /dev/sd[a-h][0-8]: individual block partitions

SEE ALSO
       scsi(4)



				  1992-12-17				SD(4)