Name

sd — Driver for SCSI Disk Drives

Synopsis

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

CONFIGURATION

The block device name has the following form: sdlp, where l is a letter denoting the physical drive, and p is a number denoting the partition 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 partition_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) parameter.

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 convenient 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 reread of the SCSI disk partition tables. No parameter is needed.

The scsi(4) ioctl(2) operations are also supported. If the ioctl(2) parameter is required, and it is NULL, then ioctl(2) will fail with the error EINVAL.

FILES

/dev/sd[a−h]: the whole device

/dev/sd[a−h][0−8]: individual block partitions

COLOPHON

This page is part of release 3.24 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


  sd.4
Copyright 1992 Rickard E. Faith (faithcs.unc.edu)

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Since the Linux kernel and libraries are constantly changing, this
manual page may be incorrect or out-of-date.  The author(s) assume no
responsibility for errors or omissions, or for damages resulting from
the use of the information contained herein.  The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
professionally.

Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.