disksecn(1M)															      disksecn(1M)

NAME

       disksecn - calculate default disk section sizes

SYNOPSIS

       block_size] [-n disk_name]

DESCRIPTION

       is used to calculate the disk section sizes based on the Berkeley disk partitioning method.

       recognizes the following options:

	      Produce tables suitable for inclusion in the device driver.

	      Produce tables suitable for generating the disk description file

	      When generating the above tables,
			     use a sector size of block_size bytes, where block_size can be or Defaults to DEV_BSIZE (defined in if not specified.

	      Specifies the disk name to be used in calculating sector sizes;
			     for example, or If an unknown disk name is specified, prompts the user for the necessary disk information.

       If neither nor table selection switches are specified a default table of the section sizes and range of cylinders used is output.

       Disk  section  sizes  are  based  on the total amount of space on the disk as given in the table below (all values are supplied in units of
       256-byte sectors).  If the disk is smaller than approximately 44 Mbytes, aborts and returns the message

	      Section	44-56MB   57-106MB   107-332MB	 333+MB
		 0	  97120      97120	 97120	  97120
		 1	  39064      39064	143808	 194240
		 3	  39064      39064	 78128	 117192
		 4	 unused      48560	110096	 429704
		 6	   7992       7992	  7992	   7992
		10	 unused     unused	unused	 516096

   Note
       It is important to note the difference between the block size passed into via the switch argument and the sector size the user is asked	to
       input when an unknown disk name is passed to via the switch argument.

       The block size is the sector size that assumes the disk to have when it prints the requested tables.  All information printed in the tables
       is adjusted to reflect this assumed sector size (block size) passed in by the user.  The sector size requested by when an unknown disk name
       is passed does not necessarily have to be the same as the assumed sector size (block size) passed in by the switch argument.

       For  example,  a  user wants to see the device driver tables for the disk named with an assumed sector size (block size) of 256 bytes.  The
       user has the following information about the disk:

	      Disk type = winchester
	      Sector size = 512
	      Number of sectors per track (512 byte sectors) = 16
	      Number of tracks = 7
	      Number of cylinders = 968
	      Revolutions per minute = 3600

       The user invokes by typing the following command:

       Assuming that is an unknown disk name, prompts the user for the necessary disk information.  The user should input the information as shown
       above,  reflecting a sector size of 512 bytes.  All the information will be adjusted within to reflect the assumed sector size (block size)
       of 256 bytes, passed as the argument of the switch, before the requested device driver table is output.

       This adjustment also takes place when the disk name is known and an assumed sector size (block size) is passed in as the  argument  of  the
       switch which is not DEV_BSIZE bytes, the assumed sector size (block size) used to create the file.

RETURN VALUE

       returns the following values:

	      Successful completion.
	      Usage error.
	      User did not input parameters for an unknown disk.
	      Disk too small or an invalid block size.

       aborts and prints an error message under the following conditions:

	 o  was invoked without specifying a disk name.
	 o  Requested both and switch.
	 o  Illegal block size requested.
	 o  Unknown disk name was specified and user did not supply disk information.
	 o  Disk's maximum storage space is less than approximately 44 MB.

WARNINGS

       Alternate names are not included in the output when the switch is used.

       Blanks are required in the command line between each of the switches when invoking

       A blank is required between the switch and the disk name argument to that switch.  For example:

       does not save the block size used to generate the disk description file.  The system assumes that the block size used was DEV_BSIZE when it
       reads the information stored in the file.

AUTHOR

       was developed by the University of California, Berkeley.

FILES

SEE ALSO

       disktab(4).

Servers Only															      disksecn(1M)