April 24, 2001, 7:40 PM —
Contents
- What is OpenBoot?
- What is the main advantage of OpenBoot?
- Why do application developers need to care about OpenBoot?
- How do I access OpenBoot?
- What is Forth doing in OpenBoot?
- What does a Forth program look like?
- How do I change the OpenBoot settings?
- How do I stop people from rebooting my workstation?
- How do I change the Power-on Banner?
- How do I boot a different kernel?
- What exactly happens during the boot process?
- Can I boot from any device?
- What are the option parameters available in booting Solaris kernels?
- What other standalone programs are available for OpenBoot?
- What is a device tree?
- How do I interpret a device tree?
- How do I create device aliases?
- What can I do with a device node?
- How do I perform device diagnostics?
- How do I make permanent changes in OpenBoot settings?
- How do I do program debugging with OpenBoot?
- At OpenBoot, can I mount file systems and access files?
- Where can I find more literature on OpenBoot and related topics?
Q: What is OpenBoot?
When you turn on a Sun workstation, the firmware in the boot PROM (programmable read-only memory) is executed immediately. The main function of a boot PROM is to load a standalone program to the core memory and start its execution. Standalone programs can be operating systems, diagnostic software, and others. The firmware in Sun's boot PROM is called OpenBoot. Other than initial program loading and invocation, OpenBoot provides debugging features to assist kernel debugging and board bring-up.
Q: What is the main advantage of OpenBoot?
Sun offers many different machine architectures (e.g., sun4d, sun4m, etc.) and boot devices (e.g., different types of disks). Instead of having different versions of the boot PROM firmware to support all combinations, OpenBoot supports plug-in device drivers. The drivers are written in a dialect of the interpreted language Forth (OpenBoot implements a Forth interpreter). The code for the driver may reside on the device PROM itself or in empty space on the system board PROM. This plug-in feature allows Sun or any third-party vendors to develop new boot devices but without recompiling or relinking the boot PROM.
Another nice thing about OpenBoot is that it behaves the same across platforms. The newer revisions provide new commands, but generally OpenBoot is stable. Sun hasn't released a major revision in more than a year.
Q: Why do application developers need to care about OpenBoot?
When the network connected to your workstation is down, and you have nothing else to do, you can always go to OpenBoot to write a Forth program to entertain yourself for a few hours. Besides that, there are many practical things you can do with OpenBoot, such as security and device diagnostics.
Q: How do I access OpenBoot?
Pressing the keys L1 and A at the same time will bring you to the OpenBoot system. You will see the display
Type b (boot), c (continued), or n (new command mode) >
You are now interacting with the restricted monitor that allows you to do three things. Typing b boots a standalone program (most likely the operating system). Typing c resumes the execution of a halted program. Typing n gets you to the Forth monitor, and the prompt will change to ok. Most of the Forth language syntax is accepted at the Forth monitor, a.k.a., the ok prompt.
ok
Now you are ready and able to do many interesting things. To continue executing (e.g., return to the OS), type
ok go
