After Power Is Switched On - Sun Microsystems SPARCstation 5 Service Manual

After Power Is Switched On

When you turn on the system power, the low-level POST phase is initiated if any of
the following circumstances apply:
4 diag-switch? NVRAM parameter is set to true.
4 Stop-d keys are held down when you turn on the power.
4 Keyboard is disconnected, and diag-switch? is set to false.
The low-level POST code, which is stored in the boot PROM, is designed to test the
most basic functions of the system hardware. The status of the POST is conveyed by
four LEDs on the Sun Type-4, Type-5, and Compact 1 keyboards. The Caps Lock
LED blinks to indicate that the tests are in progress. If a failure is detected during
low-level POST, one of the other three LEDs will light to indicate the nature of the
failure. See Chapter 3," for more information.
Note -
the Stop key.
At the successful completion of the low-level POST phase, the OpenBoot PROM
firmware takes control and performs the following initialization sequence:
4 Initialize system
4 Probe memory, then CPU
4 Evaluate Script (if use-nvramrc? is set to true)
4 Probe SBus devices and interpret their drivers
4 Install the console (see Figure 2–2)
After initialization, a system banner appears on the screen, and the high-level testing
begins. When the high-level tests are finished, the system checks parameters stored
in the NVRAM to determine the next step. Depending on the following parameter
settings, the system will:
4 Boot the operating system from a specified location, if auto-boot?is set to true
4 Suppress the boot sequence and enter the FORTH Monitor (ok prompt), if
auto-boot? is set to false
4 Continually cycle through the OpenBoot PROM sequence, if mfg-switch? is set
to true
Note -
to the OBP monitor (prompt is ok).
SPARCstation 5 Service Manual ♦ Revision A, August 1994
10
You can skip the POST phase by turning on the system while holding down
If you are in the Sunmon compatibility mode (prompt is >) type n to return