NAME

disksecn − calculate default disk section sizes

SYNOPSIS

disksecn [−p | −d] [−b block size] [−n disk name]

DESCRIPTION

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

Tables suitable for inclusion in the device driver are output. 

Tables suitable for generating the disk description file
/etc/disktab are output. 

Defines a block size in bytes to be used as the sector size in
generating the above tables.  Legal values for blocksize are 256, 512, 1024 and 2048.  Defaults to DEV_BSIZE (defined in <sys/param.h>) if not specified. 

Specifies the disk name to be used in calculating sector sizes. 
For example, hp7912 or hp7945.  If an unknown disk name is specified, disksecn will prompt 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. 

The 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 MB, disksecn aborts and returns the message "disk too small, calculate by hand". 

NOTE:
It is important to note the difference between the block size passed into disksecn via the −b switch argument and the sector size the user is asked to input when an unknown disk name is passed to disksecn via the −n switch argument. 

The block size is the sector size that disksecn assumes the disk to have when it prints out the requested tables.  All information printed out in the tables is adjusted to reflect this assumed sector size (block size) passed in by the user.  The sector size requested by disksecn 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 -b switch argument. 

For example, a user wishes to see the device driver tables output for the hp7945 with an assumed sector size (block size) of 256 bytes.  The user has the following information about the hp7945 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 disksecn by typing the following command:

disksecn -p -b 256 -n hp7945

Assuming that the hp7945 is an unknown disk name, disksecn will prompt 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 disksecn to reflect the assumed sector size (block size) of 256 bytes, passed as the argument of the −b 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 −b switch which is not DEV_BSIZE bytes, the assumed sector size (block size) used to create the etc/disktab file. 

RETURNS

Disksecn returns 0 for a successful completion, 1 for a usage error, 2 for a user not wanted to input parameters for an unknown disk and 3 for a disk that is too small or an invalid block size. 

Disksecn will abort and print out an error message under the following conditions:

Disksecn is invoked without specifying a disk name. 

Both a −p and a −d switch were requested. 

A block size other than those specified as legal is requested. 

An unknown disk name is specified and user does not wish to supply disk information. 

A disk whose maximum storage space is less than approximately 44 MB. 

WARNINGS

When using the −d switch alternate names are not included in the output

There must be spaces typed between each of the switches in the command line when invoking disksecn.

There must be a space between the −n switch and the disk name argument to that switch.  For example:

disksecn −p −b 1024 −n hp9712

At this point in time the program has no way to save the block size that was used to generate the /etc/disktab disk description file.  The system assumes that the block size used was DEV_BSIZE when it reads the information stored in the etc/disktab file. 

AUTHOR

Disksecn was developed by the University of California, Berkeley. 

FILES

/etc/disktab

SEE ALSO

disktab(4). 

Hewlett-Packard Company  —  HP-UX Release 7.0: Sept 1989