| NAME | SYNOPSIS | CONFIGURATION | DESCRIPTION | FILES | COLOPHON | The Linux Programming Interface |
SD(4) Linux Programmer's Manual SD(4)
sd - Driver for SCSI Disk Drives
#include <linux/hdreg.h> /* for HDIO_GETGEO */
#include <linux/fs.h> /* for BLKGETSIZE and BLKRRPART */
The block device name has the following form: sdlp, where l is a letter denot-
ing the physical drive, and p is a number denoting the partition on that phys-
ical 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 fol-
lows:
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.
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.
/dev/sd[a-h]: the whole device
/dev/sd[a-h][0-8]: individual block partitions
This page is part of release 3.32 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/.
Linux 1992-12-17 SD(4)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface