dparam(ADM)

dparam, dkinit -- display or change hard disk characteristics

Syntax

/bin/dparam -w [ disk_node ]
/bin/dparam disk_node [ cylinders heads wrt_reduce precomp ecc control landzone sectors ]

/etc/dkinit /dev/rhd00
/etc/dkinit [ drive controller_number controller_type ]

Description

The dparam command displays or changes the hard disk characteristics currently in effect on the disk referred to by the raw device disk_node. Any changes take effect immediately and are also written to the masterboot block for subsequent boots. If you are using a non-standard hard disk, run dparam before accessing the drive.

The default disk_node accessed by dparam is the raw device for the entire primary hard disk (/dev/rhd00).

dparam takes one option:

-w: Copies /etc/masterboot to the disk's masterboot block to ensure that non-standard hard disks are supported for the specified drive. This must precede any call to write non-standard disk parameters so that these are saved correctly in the masterboot block.

When writing characteristics for the specified hard disk, dparam changes the current disk controller status and updates the masterboot block. You must specify all the following hard disk characteristics:

cylinders: number of cylinders
heads: number of heads
wrt_reduce: cylinder number at which to start reducing the current when writing
precomp: cylinder number at which to start precompensation when writing
ecc: number of bits of error correction on I/O transfers
control: controller type number
landzone: cylinder number used to park the heads on shutting down the system (landing zone)
sectors: number of sectors per track

The parameters are specific to the type of hard disk; consult the hardware specification manual or the manufacturer for the correct information.

dkinit provides a menu-driven front end to dparam. For more details on the use of dkinit, please refer to ``Changing default disk parameters using dkinit'' in the SCO OpenServer Handbook.

Invoke dkinit with /dev/rhd00 as its argument if the primary hard disk is to be examined. To specify a different drive, supply the following three arguments:

drive

the number of the drive on a given controller; 0 or 1

controller_number

the number of the controller of a given type; 0 to 6

controller_type

the controller type:

E: OMTI disk controller
I: IDA disk controller
W: IDE, ST506 or ESDI disk controller

When installing a hard disk using mkdev hd, dkinit is invoked only for IDE, ST506, IDA, and ESDI controllers. dparam -w is run silently to write the masterboot block to SCSI and OMTI disks.

Examples

Run dparam on the root hard disk and copy /etc/masterboot to it:

/bin/dparam -w

Run dparam on the secondary hard disk:

/bin/dparam /dev/rhd10

Re-specify the hard disk characteristics of the root hard disk:

/bin/dparam /dev/rhd00 700 4 256 180 5 0 640 17

Warning

Never run dparam on a disk partition or division. If specified, disk_node must be a raw device that refers to a whole disk.

Limitations

This utility changes the kernel's view of the hard disk parameters. It may be subject to restrictions imposed by the hardware configuration.

The masterboot file is usually copied to drive 0's masterboot. Drive 1's masterboot is only used to determine virtual drive partitioning, not for masterboot code to boot up or for disk parameters. Disk parameters for both drives are kept on disk 0.

dparam copies /etc/masterboot to sector 3 (1-based) on some devices (such as Enhanced Memory Adapters). This is to prevent it overwriting the POSTEXT masterboot sector that configures the card at boot time.

Files

/dev/rhd00
/dev/rdsk/0s0: raw interface to entire primary hard disk
/dev/rhd10
/dev/rdsk/1s0: raw interface to entire secondary hard disk
/etc/masterboot: masterboot block code
/usr/lib/mkdev/perms/DKINIT: information about the hard disks configured on the system

Standards conformance

dparam and dkinit are not part of any currently supported standard; they are an extension of AT&T System V provided by The Santa Cruz Operation, Inc.