| | | |
| | h2. Open Firmware basics |
| | pSeries CHRP systems use a firmware that conforms to the open firmware IEEE Std. 1275-1994. Open Firmware is primarily a boot firmware that does not specify a particular system or processor. It also provides a machine independent devices tree interface that lists the properties of each IO device which can be displayed and altered using a command line interface. |
| | There are Open Firmware bindings for a variety of systems architectures. The one that pertains to pSeries is described in: http://playground.sun.com/1275/bindings/chrp/chrp1_8a.ps |
| | The home of the Open Firmware working group is located at: http://playground.sun.com/1275. |
| | |
| | h2. Open Firmware prompt |
| | pSeries systems can be booted to SMS or to the open firmware prompt, sometimes referred to as the ok prompt. You can reach the open firmware prompt by hitting the 8 key while booting. If under AIX, system administrators rarely have to use this. |
| | For installing Linux, however, we sometimes had to boot to the OK prompt to pass arguments to the kernel, as described in Example 2-29 on page 75. The Open Firmware prompt is also used extensively by the netboot command in CSM to boot/install from the network. SMS itself is an Open Firmware application. |
| | Next, we give a very brief introduction to the Open Firmware prompt command line interface. A quick reference guide is available from: http://www.firmworks.com/QuickRef.html |
| | A thorough description can be found at these sites: |
| | http://developer.apple.com/technotes/tn/tn1061.html |
| | http://developer.apple.com/technotes/tn/tn1062.html |
| | |
| | h2. Open Firmware Commands |
| | Booting the system in Open Firmware gives you the screen shown in |
| | |
| | {noformat} |
| | Example 2-32 Open Firmware prompt |
| | 1 = SMS Menu 5 = Default Boot List |
| | 6 = Stored Boot List 8 = Open Firmware Prompt |
| | memory keyboard network scsi speaker ok |
| | 0 > |
| | {noformat} |
| | |
| | You can navigate inside the device tree. Upon startup, you are at the top of the device tree. Use the ls command to display the device tree, a walk along all the buses and adapters that constitute the system under examination. |
