Server BIOS Switching via CPLD and BMC
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Solution Overview
Problem
The existing BIOS systems in servers are prone to failure due to errors in the BIOS image file stored in ROM, leading to unpredictable booting issues and potential system crashes, as even slight errors can result in the failure of the booting procedure.
Innovation Solution
A BIOS switching device comprising a switching module, a CPLD, a storage module, and a BMC, which allows for the selective activation of a primary or backup BIOS based on logic output signals, enabling users to switch to a backup BIOS when the primary one fails, without modifying the original hardware, using a switching element, hardware pins, and user input via a screen and keyboard to manage BIOS activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single BIOS is stored in ROM, then the hardware configuration remains simple, but the system reliability deteriorates because any error in the BIOS image file causes booting failure
Solution Approach 1:
The BIOS system is segmented into multiple independent BIOS images (first BIOS and second BIOS) stored in separate regions of the storage module. This segmentation allows the system to switch between different BIOS versions, improving reliability by enabling fallback to a backup BIOS when the primary one fails, while keeping each individual BIOS image relatively simple in structure.
Solution Approach 2:
A second BIOS image is pre-stored in the storage module as a backup before any failure occurs. The BMC performs preliminary detection of the BIOS image integrity and pre-configures the switching capability. When the primary BIOS fails, the system can immediately switch to the pre-prepared backup BIOS without requiring external intervention or complex recovery procedures.
2Reliability
If BIOS switching capability is added to handle failures, then the system reliability improves, but the hardware configuration and device complexity increase
Solution Approach 1:
The BMC serves multiple functions: it manages the storage module, detects BIOS image integrity, controls the switching element, and activates the appropriate BIOS. By making the BMC multi-functional, the patent avoids adding dedicated separate components for each function, thereby improving reliability through comprehensive BIOS management while minimizing the increase in hardware complexity.
Solution Approach 2:
The patent merges the BIOS switching control logic with the existing BMC (Baseboard Management Controller) rather than adding a separate dedicated switching controller. The BMC integrates multiple functions including BIOS image detection, switching element control, and BIOS activation management into a single component, reducing the overall hardware complexity while maintaining the ability to switch between BIOS images for improved reliability.
3Productivity
If automatic BIOS switching is implemented, then the booting speed improves, but the device complexity increases due to additional detection and control mechanisms
Solution Approach 1:
The BMC performs preliminary detection of BIOS image integrity during the power-on process before the actual booting begins. By detecting and validating the BIOS image in advance and pre-configuring the switching element, the system avoids time-consuming detection and switching operations during the critical booting phase, thereby improving booting speed while the control complexity is managed through automated preliminary actions.
Solution Approach 2:
The BMC automatically detects BIOS image integrity, determines whether switching is needed, and activates the appropriate BIOS without requiring external intervention. The system performs self-diagnosis and self-correction by automatically switching to a backup BIOS when the primary one is detected as faulty, improving booting speed by eliminating manual intervention while the control mechanisms remain integrated within the BMC.
Data Source
AI summary
A BIOS switching device adapted to a server comprises a switching module, a CPLD, a storage module and a BMC. The switching module comprises a movable switching element locating at a first position or at a second position and a plurality of hardware pins. The hardware pins are logical low when the switching element locates at the second position and remains unchanged logical level when the switching element locates at the first position. The CPLD electrically connects to the switching module, comprising a plurality of input signals respectively coupled to the plurality of hardware pins. The CPLD generates an output signal according to the plurality of input signals. The BMC activates a first BIOS or a second BIOS from the storage module according to the logical level of the output signal of the CPLD.