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 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.
The following ioctls are
provided:
HDIO_GETGEOReturns 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
notthe 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.
BLKGETSIZEReturns the device size in sectors. The ioctl(2) parameter
should be a pointer to a long.
BLKRRPARTForces a re-read 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.
This page is part of release 2.79 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/.
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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. |