Service manual

System Overview 1-13

NOTE: The LEDs on some modules are on when the line cord is plugged in,

regardless of the position of the On/Off button.

➋ Halt button. Pressing this button in (so the LED at the top of the button is on)

does the following:

If DIGITAL UNIX or OpenVMS is running, halts the operating system and

returns to the SRM console. The Halt button has no effect on Windows NT.

If the Halt button is in when the system is reset or powered up, the system halts

in the SRM console, regardless of the operating system. DIGITAL UNIX and

OpenVMS systems that are configured for autoboot will not boot if the Halt

button is in. Windows NT systems halt in the SRM console; AlphaBIOS is not

loaded and started.

If you press the Halt button in (LED on) and do not issue commands that

disturb the system state, entering the continue command returns the system to

the operating system it was running. To return to console mode again, press

the Halt button (LED off) and then press it again (LED on).

If the system is hung, pressing the Halt button (LED on) usually brings up the

SRM console. Enter the crash command to do a crash dump. If pressing the

Halt button does not bring up the SRM console, there is probably a hardware

fault that is not allowing the halt signal to pass from the XBUS to the CPU.

➌ Reset button. Initializes the system drawer. If the Halt button is pressed (LED

on) when the system is reset, the SRM console is loaded and remains in the

system regardless of any other conditions.

➍ Control panel display. Indicates status during power-up and self-test. The

OCP display is a 16-character LCD. Its controller is on the XBUS on the PCI

motherboard.

While the operating system is running, displays the system type as a default.

This message can be changed by the user.

CD-ROM drive. The CD-ROM drive is used to load software, firmware, and

updates. Its controller is on PCI1 on the PCI motherboard.

Floppy disk drive. The floppy drive is used to load software and firmware

updates. The floppy controller is on the XBUS on the PCI motherboard.