The SGI 1200 server motherboard can be populated with up to two Intel Pentium III processors. The processors on the motherboard must be rated at the same clock speed. Contact your sales or customer support representative for information on upgrading your server's processors.

The motherboard supports from 128 MB to 2 GB of 100 MHz PC/100 SDRAM memory. The system supports only error correcting code (ECC) memory. Contact your sales or system support representative for server memory upgrades.

Figure 2-3 shows the basic cabling routes. Moving from left to right:

Figure 2-4 shows cabling routes without the optional PCI-based RAID controller:

External connections are not shown. All configurations support an optional Ultra SCSI connector for external SCSI devices. See Figure 2-11Figure 2-11Figure 2-11 for the location of this connector on the back panel and Table 4-1 for additional information.

Figure 2-3. SCSI Cabling Route to Midplane with Optional RAID Controller

Figure 2-4. SCSI Cabling to Midplane without Optional RAID Controller

The SCA midplane on the SGI 1200 server provides easy hard drive removal and replacement. Adding a RAID controller supports hot-swap capability for SCA-2 hard drives using Ultra2 SCSI technology on a single channel. All bus termination and SCSI ID selection for SCA hard drives is handled automatically by the midplane.

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Note: The midplane does not support single ended SCSI devices.

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The SCA midplane uses Qlogic's GEM processor to implement the SAF-TE (SCSI Accessed Fault Tolerant Enclosure) specification. The processor monitors the removal and replacement of Ultra-2 SCSI SCA hard drives, scans the SCSI bus for errors, and senses chassis over-temperature and failed fan conditions.

The following SCSI error conditions are indicated as failures:

Figure 2-5 shows the SCSI IDs that the midplane assigns. The midplane itself uses SCSI ID 9.

Figure 2-5. Midplane-Assigned SCSI IDs

Temperature sensors on the right and left side of the midplane monitor the chassis temperature. When the sensors detect internal chassis temperatures above 50 degrees C (equipment damaging conditions), the midplane issues a signal that causes the amber Global Failure LED on the front panel to light.

The chassis fans are also monitored, and a fan failure causes the Global Failure LED to light.

There are two push buttons and several LEDs on the right hand side of the SGI 1200 server front panel. The following sections provide information about the buttons and LEDs on the front and back panel, and information about error conditions that the LEDs can indicate. The information in this section can help you make a quick visual inspection of the status of the hard drives, network connections and internal components of your SGI 1200 server.

If the amber Global Failure LED that you can view through the front cover does light, you can use the information in this section, and Chapter 5 to troubleshoot the failure source.

Figure 2-7. Front Panel Push Buttons (Cover Removed)

Front AC Power Push Button

Pressing this button powers on the SGI 1200 server. If you decide that you don't want to power up the SGI 1200 server, press the button again to immediately shut down the system. The blue LED will blink briefly and the server shuts down before the BIOS or operating system are initialized.

When the SGI 1200 server is operating, holding this button for five seconds issues a shutdown command to the system.

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Warning: The SGI 1200 server continues to have AC power inside the chassis even after the front power push button has been pressed to power down the SGI 1200 server. As long as the AC power cord is connected, the power supply supplies DC power so that the motherboard can be controlled through the Emergency Management Port (EMP) for remote management, fan usage and processor cooling. Factory authorized service personnel must unplug the AC cord before opening the chassis for service.

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Reset Push Button

The reset push button connects to the motherboard. If the SGI 1200 server freezes during use, pressing the reset button issues a hardware reset to the BIOS, and the operating system reloads.

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Caution: Pressing the reset button is the last resort for dealing with a non-responsive server. Any work not saved to disk will be lost when the reset button is pressed. Pressing the reset button can leave the operating system in an uncertain state, so try logging into an alternate console to cancel a runaway process before you reset your system. Check with your system administrator.

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Figure 2-8. Front Panel LEDs  

Green Disk LED

The green LED located beneath the blue AC power LED is the disk activity LED. It flickers during disk activity.

Ethernet Activity LED

The green Ethernet activity located above the amber Global Failure LED flickers during 100 and 10 Mbps Ethernet activity.

Amber Global Failure LED

There are a variety of failure conditions that cause the amber Global Failure LED to light, including:

• AC power into the power supply out of normal range

• DC power outputs from the power supply not within specified range

• A variety of hard disk drive failure conditions (see the troubleshooting section of Chapter 5 for more details)

• Chassis detects temperatures that exceed the acceptable ranges

• Fan failure

Table 2-1 provides a summary of the front panel LED states.

Table 2-1. Front Panel LED State Summary

LED	Normal Status During Use	Problem Indication
AC Power LED	Bright blue	LED not lit
Disk Activity LED	Blinks green during any hard disk activity	LED never flickers
Network Activity LED	Blinks green during 10 and 100 Mbps network activity	LED never flickers
Global Failure LED	LED not lit	Solid amber LED, or very slow blinking amber LED

Hard Drive Carrier LEDs

Figure 2-9 shows the location of the green and red hard drive carrier LEDs.

Figure 2-9. Hard Drive Carrier LEDs

Table 2-2 provides a summary of the LEDs on the hard drive carrier.

Table 2-2. Hard Drive Carrier LED State Summary

LED	Normal Status During Use	Problem Indication
Green LED	LED blinks during hard drive disk read and write activity	LED not lit
Red LED	LED never lit	LED blinks or lit

Power Supply LEDs

As Figure 2-10 shows, there are two LEDs next to the power supply.

Figure 2-10. Power Supply LEDs

The amber LED lights when the AC power cord is plugged into the AC power cord receptacle. This indicates that the power supply is supplying the chassis with +5V standby for EMP port control. The amber LED turns off when the rocker switch above the AC power receptacle is switched on and the chassis receives all DC power. A lit green LED indicates the chassis is powered up.

Table 2-3 provides a summary of the LEDs on the power supply.

Table 2-3. Power Supply LED State Summary

LED	Normal Status During Use	Problem Indication
Green LED	LED lit	Green LED does not light after power switched on
Amber LED	LED lit when AC cord plugged in, amber LED turns off when AC rocker switch turned on	Amber LED remains lit after power switched on

Back Panel Connectors

Figure 2-11  shows the SGI 1200 server backpanel.

Figure 2-11. Connectors on the SGI 1200 Server Back Panel