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disktab(5) [bsd man page]

DISKTAB(5)							File Formats Manual							DISKTAB(5)

disktab - disk description file SYNOPSIS
#include <disktab.h> DESCRIPTION
Disktab is a simple date base which describes disk geometries and disk partition characteristics. The format is patterned after the term- cap(5) terminal data base. Entries in disktab consist of a number of `:' separated fields. The first entry for each disk gives the names which are known for the disk, separated by `|' characters. The last name given should be a long name fully identifying the disk. The following list indicates the normal values stored for each disk entry. Name Type Description ns num Number of sectors per track nt num Number of tracks per cylinder nc num Total number of cylinders on the disk b0 str Filename of block zero primary bootstrap for device ba num Block size for partition `a' (bytes) bd num Block size for partition `d' (bytes) be num Block size for partition `e' (bytes) bf num Block size for partition `f' (bytes) bg num Block size for partition `g' (bytes) bh num Block size for partition `h' (bytes) fa num Fragment size for partition `a' (bytes) fd num Fragment size for partition `d' (bytes) fe num Fragment size for partition `e' (bytes) ff num Fragment size for partition `f' (bytes) fg num Fragment size for partition `g' (bytes) fh num Fragment size for partition `h' (bytes) pa num Size of partition `a' in sectors pb num Size of partition `b' in sectors pc num Size of partition `c' in sectors pd num Size of partition `d' in sectors pe num Size of partition `e' in sectors pf num Size of partition `f' in sectors pg num Size of partition `g' in sectors ph num Size of partition `h' in sectors se num Sector size in bytes (default 512) sf bool supports bad144-style bad sector forwarding so bool partition offsets in sectors ty str Type of disk (e.g. removable, winchester) Disktab entries may be automatically generated with the diskpart program. FILES
/etc/disktab SEE ALSO
newfs(8), diskpart(8), getdiskbyname(3) BUGS
This file shouldn't exist, the information should be stored on each disk pack. 4.2 Berkeley Distribution May 17, 1986 DISKTAB(5)

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NEWFS(8)						      System Manager's Manual							  NEWFS(8)

newfs - construct a new file system SYNOPSIS
/sbin/newfs [ -N ] [ -m free-gap ] [ -n free-modulus ] [ -i bytes ] [ -s size ] [ -T disk-type ] special DESCRIPTION
Newfs is a ``friendly'' front-end to the mkfs(8) program. Newfs(8) will normally read the disklabel from the drive to determine the parti- tion sizes. If the driver for the disk does not support disklabels the -T option must be used to force a search of /etc/disktab for parti- tion information about drive-type. Newfs calculates the appropriate parameters to use in calling mkfs, then builds the file system by forking mkfs. -N causes the mkfs command which would be executed to be printed out without actually creating the file system. The disk specified by spe- cial must be online though so that newfs can read the disklabel. -m allows the specification of the block interleaving of the free list. If not specified or outside the range 1 thru 32 then a value of 2 is used. -n parameter is the freelist modulus (when the -m pattern repeats) and is calculated by newfs to be 1 cylinder in size by default. -i specifies how many bytes per inode to assume when calculating how many inodes to allocate. The default is 4096 bytes per inode. If this results in too few inodes being allocated (there is an absolute maximum of 65500) then decrease the bytes number (which must lie between 512 and 65536). -T must be used if the disk specified by special has not been labeled with the disklabel(8) program. In this case disk-type is used by getdisklabel(3) when searching /etc/disktab. This option is used when the underlying device driver does not support disklabels. Care must be taken that the contents of /etc/disktab match the partition tables in the kernel. -s specifies how many sectors the file system is to contain. There are two sectors per file system block, therefore size should be even. This parameter must be less than or equal to the partition size (as determined from the disklabel or /etc/disktab). An error is printed and no action is taken if the partition size is 0 or too large. NOTE: Mkfs deals in units of filesystem blocks not sectors. Newfs uses sectors. FILES
/etc/disktab disk geometry and partition information mkfs to actually build the file system SEE ALSO
getdisklabel(3), disklabel(8), disktab(5), diskpart(8), fs(5), fsck(8), mkfs(8) BUGS
newfs(8) no longer places boot blocks on the filesystem. That duty has been moved to the disklabel(8) program. If you must place a boot block on a disk whose driver does not support disklabels use dd(1). 4.2 Berkeley Distribution April 12, 1996 NEWFS(8)
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