Sparc/OBP Reference

The OpenBoot PROM (OBP) Reference provides a list of useful OBP commands that can help when booting, configuring and performing diagnostics upon Sun SPARC hardware and clones.

About this Document
This document provides a list of useful OBP commands that can be helpful when booting, configuring and performing diagnostics upon Sun SPARC hardware and clones.

Note that not all commands are available on all PROM versions. In particular, sun4c systems have a different input mode, and some JavaStation models are missing a lot of OBP functionality.

OBP is somewhat inconsistent when it comes to command names. Sometimes hyphens are used to separate words, sometimes they are not. Some commands which display information start with or contain a dot (this is a FORTH convention).

The terms "OBP", "OpenBoot PROM" and "PROM" are used interchangeably in this document.

Systems with Sun Keyboards
On regular Sun systems (and clones which use Sun keyboards), press  when the system boots to enter OBP. The  key is the top left key on the extra block of keys on the left hand side of the keyboards (on really old systems it might be marked   ).

The  keyboard combination at boot will reset many systems to the default PROM settings. will enable diagnostics on some boards.

Over Serial Console
To enter OBP over serial console, send a break. In minicom, do this by pressing. In xc, use.

Systems with Non-Sun (PC Style) Keyboards
On systems with PC-style keyboards (such as JavaStations and some Ultra clones),  or   is generally used.

Note that on the JavaStation JK,  will restart the box rather than enter PROM. To get at OBP, you will need to set jumper J1300 pins 7-8 on the mainboard.

Halting and Restarting
The  command will halt the box and turn off power. This command is sometimes screwy on Ultra5/10 systems.

The  command will perform a soft reset. If diagnostics are enabled, they will not be rerun. In some documents, this command is referred to as.

The  command boots the system. A parameter may be provided to override the default boot device -- this can be a full device name or a device alias such as ,   or. Any additional arguments are passed to the bootloader or operating system.

PROM and System Information
The  command will show the OBP version.

The  command will show the system information banner.

The  command will show bus speeds.

Device Information
The  command will give a list of devices available to the system.

The  command will show internal SCSI devices available to the system. The  command will show both internal and external devices on every SCSI interface. After running either of these commands, you must issue a  before trying to boot an operating system.

The  command is also available on IDE-based systems.

Getting and Setting Environment Variables
Use  to get a list of environment variables. To see the value of a specific variable, use.

To set a variable, use.

To restore a variable's default value, use. To revert all variables to default, use.

Note that boolean variables usually end in a , and that they are separate from variables of the same name without the question mark. The values  and   are used for booleans.

Useful Environment Variables
Some useful environment variables:

Getting and Setting Device Aliases
Device aliases can be used to simplify the arguments to many commands. Instead of typing , for example, one could use. A number of device aliases are defined by default on every system.

To view all device aliases, use the  command. To view a specific alias, use. To set a device alias, use.

Changing Monitor Resolutions
The  variable can be used to control which framebuffer is used, and at what resolution it is run, for PROM console. For example, to use the Creator card on an Ultra 1C or 2 at a resolution of 1024x768@76Hz:

Changes will not take effect until after a reset. Not all resolutions and refresh are available on all cards.

Entering Diagnostic Mode
Before running any diagnostics, it is best to enable  and do a full power off / on cycle (hard power off). Additional diagnostic information will be provided over the serial console when the machine boots.

Basic Tests
If the power on self test (POST) succeeds, additional tests can be performed using the ,   ,   and   commands.

The  command will perform checks upon the specified device (this can be a full device path or a device alias).

The  command will perform checks upon every device capable of self tests.

The  command can be used to watch for broadcast packets being sent over the network.

The  command can be used to verify that the internal clock is working. It should count from 0 to 59 in a loop with an interval of one second.

Extended Diagnostics Using obdiag
To enable extended diagnostics mode, run the following:

This should display a menu. First, select  to enable verbose messages.

Individual tests can then be run by selecting the relevant number. Note that some tests (for example, serial ports) assume that an external loopback connector is attached. The Ethernet test assumes that a cable is attached and connected to a switch.

To exit, use.