disksecn(1M)disksecn(1M)NAMEdisksecn - 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 speci‐
fied, 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 neces‐
sary 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:
· was invoked without specifying a disk name.
· Requested both and switch.
· Illegal block size requested.
· Unknown disk name was specified and user did not supply disk
information.
· 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.
FILESSEE ALSOdisktab(4).
Servers Onlydisksecn(1M)
