Appendix D: LED Decoder

During the system boot process, BIOS executes a number of platform configuration processes, each of which is assigned a specific hex POST code number. As each configuration routine is started, BIOS will display the given POST code to the POST Code Diagnostic LEDs found on the back edge of the server board. To assist in troubleshooting a system hang during the POST process, the Diagnostic LEDs can be used to identify the last POST process to be executed.

Each POST code will be represented by a combination of colors from the four LEDs. The LEDs are capable of displaying three colors: green, red, and amber. The POST codes are divided into two nibbles, an upper nibble and a lower nibble. Each bit in the upper nibble is represented by a red LED and each bit in the lower nibble is represented by a green LED. If both bits are set in the upper and lower nibbles then both red and green LEDs are lit, resulting in an amber color. If both bits are clear, then the LED is off.

In the below example, BIOS sends a value of ACh to the diagnostic LED decoder. The LEDs are decoded as follows:

•red bits = 1010b = Ah

•green bits = 1100b = Ch

Since the red bits correspond to the upper nibble and the green bits correspond to the lower nibble, the two are concatenated to be ACh.

Table 11. POST Progress Code LED Example

 

 

8h

 

4h

 

2h

 

1h

 

 

 

 

 

 

 

 

 

 

 

 

 

LEDs

Red

 

Green

Red

 

Green

Red

 

Green

Red

 

Green

 

 

 

 

 

 

 

 

 

 

 

 

 

ACh

1

 

1

0

 

1

1

 

0

0

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

Result

Amber

 

 

Green

 

 

Red

 

 

Off

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MSB

 

 

 

 

 

 

 

LSB

 

 

 

 

 

 

 

 

 

 

 

 

 

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Intel SR1550ALSAS manual Appendix D LED Decoder, LEDs Red Green
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SR1550AL, SR1550ALSAS specifications

The Intel SR1550ALSAS and SR1550AL servers are designed to provide reliable and high-performing solutions for various enterprise applications. Built on Intel's robust architecture, these server systems cater to businesses seeking efficient data management, scalable infrastructure, and effective virtualization support.

One of the main features of the SR1550 series is its dual-socket capability, accommodating Intel Xeon processors, which deliver exceptional multi-threaded performance. This allows organizations to enhance processing power to handle demanding workloads effectively, such as databases, transactional applications, and virtualization tasks. The server can support a significant amount of RAM, typically up to 512 GB of DDR3 memory, ensuring ample resources for modern applications requiring substantial memory bandwidth.

The SR1550 model comes equipped with various storage options to support large data sets. With support for multiple SATA and SAS drives, users can configure the server to meet their performance needs, whether it is for fast access speeds or high-capacity storage requirements. Hot-swap drive bays improve maintenance efficiency, allowing administrators to replace drives without downtime.

In terms of connectivity, the SR1550 servers feature multiple Ethernet ports and expansion slots, providing flexibility for network configurations and the integration of additional components. The server supports PCIe slots for adding GPUs, RAID controllers, or additional network interfaces, enhancing versatility and performance for various use cases.

The SR1550 series also incorporates advanced management features to simplify administration. The Intel Integrated Lights Out Manager (ILOM) allows remote monitoring and management, which is crucial for maintaining uptime and performing troubleshooting without physical access to the hardware.

Another significant characteristic is the design's attention to energy efficiency. Intel's architecture optimizes power consumption, and advanced cooling techniques ensure that the system operates under thermal thresholds, thus maximizing performance while managing energy usage effectively.

In summary, the Intel SR1550ALSAS and SR1550AL servers combine a powerful processor architecture, scalability, extensive storage options, comprehensive management features, and energy efficiency. These characteristics make them suitable for diverse applications, ensuring that businesses can meet their performance and reliability needs in an ever-evolving IT landscape.
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