Testing the Polled I/O Interfaces

The polled I/O interfaces are only available under the following circumstances:

• When you enter the OpenBoot PROM by using the L1+A keystroke sequence

• When you boot the system with a standalone debugger such as kmdb(1)

• When the system panics

The polled I/O interfaces only become available at a certain point in the boot process. Polled I/O requests issued from the OpenBoot PROM before the system is running are not rendered. Similarly, kmdb prompts issued before the console is configured are not rendered.

To test the polled I/O interfaces, enter the OpenBoot PROM by using the L1+A keystroke sequence. To validate that the polled I/O interfaces are being used, type the following command at the OpenBoot PROM ok prompt:

ok 1b emit ." [32m This is a test" 1b emit ." [m"

The polled I/O interfaces are working properly if the following statements are true:

• The result of the above command is that the phrase This is a test is displayed in green.

• The OpenBoot PROM continues to function correctly.

• Scrolling performs as expected.

• The cursor displays correctly.

• The system can be reentered and continued repeatedly.