dparam(ADM)

dparam -- display hard disk characteristics

Syntax

/bin/dparam [ -w ] [ disk_node ]

Description

The dparam command supports writing the masterboot block of a hard disk and displaying disk parameters.

Previous versions of dparam supported changing hard disk characteristics; this is no longer supported. The system detects and sets hard disk configuration parameters automatically. All hard disk parameters in use reflect the values used by the system BIOS. The dkinit command, which provided a menu-driven front end to dparam in previous releases, is also no longer supported.

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

dparam supports 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.

The following hard disk characteristics are printed by dparam, in this order:

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.

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

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

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 is not part of any current standard specification.