sd (4)
Leading comments
sd.4 Copyright 1992 Rickard E. Faith (faith@cs.unc.edu) %%%LICENSE_START(VERBATIM) 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. Sin...
NAME
sd - driver for SCSI disk drivesSYNOPSIS
#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.
-
Returns the BIOS disk parameters in the following structure:
- 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 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