NAME

ddefs − disk definition information manager

SYNOPSIS

/etc/ddefs [-dddefsdir] -n[diskname]
/etc/ddefs [-dddefsdir] -erpdiskname

DESCRIPTION

The ddefs utility is used to add to or modify the information that describes disks.  The disk definitions are contained in files in the /etc/dskdefs directory.  The files in /etc/dskdefs are read by the dinit(1M) program to obtain format information about the disks. 

To specify the directory, use the −d option followed by a directory name on the command line, as shown in the SYNOPSIS section.  If no ddefsdir is given, the default is /etc/dskdefs. 

The diskname is either a “device”, specified as /dev/rdsk/devicename, or a “ddefs file” in the directory ddefsdir. 

The ddefs program provides several options both for interactive and non-interactive use.  UNIX System V/68 and UNIX System V/88 only support the 182Mb CDC WREN; however, this command contains additional options for other controllers and drives.  The options are:

-n [diskname]
(Interactive) Create a new disk definition, where diskname corresponds to the type values listed for dinit(1M).  If a name is given that already exists, the program automatically shifts to edit mode (-e option).  If no diskname is given, the user is prompted for a name.  When creating a new definition, ddefs will prompt for the name of a “template” disk.  The template disk is usually one with similar, but not identical, attributes. 

-e diskname
(Interactive) Edit an existing disk definition. If the diskname given does not exist, the program switches automatically to create mode (-n option). 

-r diskname
(Interactive) Edit an existing disk definition (read-only).

-p diskname
(Non-interactive) Print an existing disk definition.

For every type of operation, the user has the option of specifying a directory for the disk definition file.  If an existing definition is being edited, this is the directory where the definition file can be found.  If a new definition is being created, this is the directory where the definition file will be placed.  It is also the directory where the template can be found when this feature is used. 

Each disk definition is formatted as a series of lines, each line giving a parameter name followed by a value.  To modify a definition, move the cursor to the appropriate line and type the new value.  When creating a new definition file, ddefs will not write the definition until all parameters are initialized (changed). 

To obtain “help” information about a parameter, type a ? after the parameter name.  The elements of the definition file and the help information for each are given in the following paragraphs. 

When diskname is a “ddefs file”, all parameters are readable and writeable.  When diskname is a device, the following conventions are used to indicate how a parameter may be accessed: a single asterisk (∗) following a parameter name indicates that the user has read access in interactive mode; a double asterisk (∗∗) indicates that the parameter may be read and written in interactive mode; no asterisk indicates that the parameter is not applicable for a raw device (that is, the parameter exists only in the ddefs file). 

Comment
This information is general comments. It cannot contain more than one line. Usually, the comment information is a description of the drive type supported by the definition file. If no comment is desired, type none. 

Disk type∗∗
This value is any unique integer that is used to identify the disk drive type. Each size drive on each controller should have a different type.

Format command
The format program, if specified, is called by dinit(1M) to format a disk drive.  The format program line should specify all options necessary to format the disk.  All drives supported by UNIX System V/68 and UNIX System V/88 can be formatted directly by dinit(1M).  Therefore this field should be specified as none. 

Diagnostic tracks∗
To reserve diagnostic tracks, type yes.  If not, type no. 

Bad spot strategy∗
If the controller only supports perfect media, type perfect. 

BAD TRACKS: If bad track replacement is done by the bad track replacement software, type software.  If the controller automatically performs bad track replacement, type hardware.  BAD SECTORS: If the controller supports automatic bad sector replacement and requires the cylinder, head, and sector of each bad sector, then type sector.  BAD SPOTS: If the controller supports automatic bad spot replacement and requires the cylinder, head, and byte offset of each bad spot, then type spot. 

Maximum number of bad spots
This value is the maximum number of bad spots expected on a disk of this type. This many alternate spots (sectors or tracks) will be allocated for this drive.

Number of sectors∗∗
This value is the total number of sectors on the disk drive.

Sector size (in bytes)∗∗
This value is the disk sector size (specified in bytes). Currently, it must be 128, 256, or 512 bytes. 

Sectors per track∗∗
This value is the number of usable sectors per track on the formatted media.

Cylinders∗∗
This value is the total number of cylinders on the disk media.

Heads∗∗
This value is the number of read/write heads on the drive. It is equivalent to the number of tracks per cylinder.

Precompensation cylinder∗∗
This value is the disk cylinder number to start write precompensation.

Sector interleave∗∗
This value is the sector interleave factor used during disk formatting. For no interleave (or one-to-one interleave), type 1.  Some controllers will automatically select an appropriate interleave factor when given an interleave value of 0. 

Spiral offset∗
This value is the spiral offset applied when formatting disks. If no spiral offset is wanted, then type 0. 

Step rate∗∗
This value is the seek step rate used when accessing the disk. Some controllers will automatically select an appropriate step rate when given a step rate of 0.

Starting head number∗∗
This value is the starting head number of the drive. Most drives and controllers require a starting head number of zero.

ECC error length∗∗
This value is the error correcting code data burst length.

Attributes mask (hex)∗∗
This value is the disk attributes mask. Bits in this mask determine which bits in the attributes word are valid.

Extended attributes mask (hex)∗∗
This value is the extended attributes mask.

Attributes word (hex)∗∗
This value is the disk attributes word. The (hexadecimal) bit definitions are:

Extended attributes word (hex)∗∗
This value is the extended attributes word.

Gap byte 1 (hex)∗∗
This value is the first ‘gap byte’ required for formatting a disk. This parameter is controller-and drive-specific and may not be used by some controllers.

Gap byte 2 (hex)∗∗
This value is the second ‘gap byte’ required for formatting a disk. This parameter is controller-and drive-specific and may not be used by some controllers.

Gap byte 3 (hex)∗∗
This value is the third ‘gap byte’ required for formatting a disk. This parameter is controller-and drive-specific and may not be used by some controllers.

Gap byte 4 (hex)∗∗
This value is the fourth ‘gap byte’ required for formatting a disk. This parameter is controller-and drive-specific and may not be used by some controllers.

Controller attribute (hex)∗∗
This value is controller-and drive-specific information and may not be used by some controllers.

Unformatted sector size∗∗
This value is the unformatted sector size on the disk including the headers, gaps, ECC, and data. This parameter is controller and drive-specific, and may not be used by some controllers.

Sector slip count∗∗
This value is the sector slip count used while formatting to implement controller supported sector slipping. This count is the number of ‘slip’ sectors per track.

Slice count∗
This value is the dynamic slice count. If zero, the driver will not use dynamic slicing. Legal non-zero slice counts are 8, 16, 32, 64, and 128. Some controllers support only a subset of these legal slice counts.

Root file system offset∗
This value is the 1024-byte block offset of the root file system. 

Root file system size
This value, if non-zero, is the size of the root file system (in 512-byte blocks) created on slice zero of the drive after it is formatted.  If no file system is desired, then type 0. 

/usr file system size
This value, if non-zero, is the size of the /usr file system (in 512-byte blocks) created in slice one or two after the drive is formatted.  If no /usr file system is desired, type 0.  The /usr file system is created only if a root file system is also created. 

/usr file system slice
This value specifies the slice for the /usr file system.  This value must not be zero but may coincide with the swap slice. 

Swap size
This value, if non-zero, specifies the size of the system swap space (in 512-byte blocks). The swap space will be placed following the root file system if the swap slice is set to zero.  If the swap slice and the /usr file system slice are both one, swap follows the /usr file system in slice one. 

Swap slice
This value specifies the swap slice. It may be set to zero (to share the root file system slice), or to one (to occupy its own slice or share with the /usr file system), or to two (to occupy its own slice following the /usr file system slice). 

End-of-disk reserved area
This value is the number of blocks reserved for system use at the end of the disk. This area may be used for bad track alternates or for diagnostic tracks.

Alternates list
To add to the alternates list, type add #[-#].  To delete from the alternates list, type delete #[-#].  The ‘#’ is any non-zero number.  The sequence ‘#-#’ specifies a range of non-zero numbers (including the end-points).  To have no alternates, type none.  The value printed in parentheses is the total number of alternates in the list. 

When creating a disk description using ddefs, the following information must be given to have dinit(1M) create a slice table:

a non-zero slice count; currently restricted to 0, 8, 16, 32, 64, 128

the root file system offset

the root file system size

the size of swap (if any)

if swap is defined, what slice it resides on (allowable slices: 0, 1, 2)

the /usr file system size (if any)

if /usr is defined, what slice it resides on (allowable slices: 0, 1, 2)

the size of the “end-of-disk” reserved area.  This area is used for diagnostic and/or alternate tracks. 

NOTES

The elements “root file system size”, “/usr file system slice”, “swap size”, and “swap slice” are not used and are present to maintain backwards compatibility. 

FILES

/etc/dskdefs/∗disk definition file

SEE ALSO

dinit(1M)