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newfs(8) [bsd man page]

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)

Check Out this Related Man Page

creatediskbyname(3x)													      creatediskbyname(3x)

       creatediskbyname - get the disk description associated with a file name

       #include <disktab.h>

       struct disktab *
       char *name;

       The subroutine takes the name of the character device special file representing a disk device (for example, and returns a structure pointer
       describing its geometry information and the default disk partition tables.  It obtains this information by  polling  the  controlling  disk
       device driver.  The subroutine returns information only for MSCP and SCSI disks.

       The file has the following form:
       #define DISKTAB	      "/etc/disktab"

       struct  disktab {
	     char   *d_name;	      /* drive name */
	     char   *d_type;	      /* drive type */
	     int    d_secsize;	      /* sector size in bytes */
	     int    d_ntracks;	      /* # tracks/cylinder */
	     int    d_nsectors;       /* # sectors/track */
	     int    d_ncylinders;     /* # cylinders */
	     int    d_rpm;	      /* revolutions/minute */
	     struct partition {
		     int     p_size;   /* #sectors in partition */
		     short   p_bsize;  /* block size in bytes */
		     short   p_fsize;  /* frag size in bytes */
	       } d_partitions[8];

       struct  disktab *getdiskbyname();
       struct  disktab *creatediskbyname();

       Successful completion of the subroutine returns a pointer to a valid disktab structure.	Failure of this subroutine returns a null pointer.
       The subroutine fails if it cannot obtain the necessary information from the device driver or disktab file.

       A check is done to ensure that the disktab file exists and is readable.	This check ensures that the subroutine is not being called because
       the disktab file was accidentally removed.  If there is no disktab file, the subroutine fails.

       The subroutine also fails if it cannot determine disk geometry attributes by polling the driver.  This can occur if the disk is not an MSCP
       or SCSI disk.  In some cases where the disk consists of removable media and the media is not loaded, the driver will be unable to determine
       disk attributes.

       The subroutine returns information only for MSCP and SCSI disks.

See Also
       getdiskbyname(3x), ra(4), rz(4), disktab(5)


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