Linux Man Pages

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: sd lp, 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 ioctl s are provided:

HDIO_GETGEO

Returns the BIOS disk parameters in the following structure:

Returns the BIOS disk parameters in the following structure:

struct hd_geometry {
     unsigned char  heads;
     unsigned char  sectors;
     unsigned short cylinders;
     unsigned long  start;
 };
 
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 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 . 

FILES

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

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

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