SATA Host Interface Circuit for SAS Fabric Scalability
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Solution Overview
Problem
Current SATA storage systems lack the flexibility and scalability of SAS architectures, limiting the configuration and expansion capabilities, especially in using simpler and less costly SATA hosts and target devices within a SAS fabric domain.
Innovation Solution
An enhanced SAS expander is introduced, supporting direct coupling of SATA hosts with a SAS fabric through SATA/STP logic, enabling SATA protocol exchanges between SATA hosts and target devices via the SAS fabric, allowing multiple SATA hosts to connect with a larger number of SATA target devices and simplifying the architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If SATA hosts are directly coupled with SATA target devices using standard SATA architecture, then the system uses simpler and less costly SATA initiators, but the system lacks flexibility and scalability in configuration and expansion
Solution Approach 1:
A SATA host interface circuit is introduced as an intermediary component between the SATA host and the SAS fabric. This interface circuit enables SATA hosts to communicate with SATA target devices through the SAS fabric by translating SATA protocols into SAS protocols, allowing simpler SATA hosts to be used while gaining SAS architecture flexibility and scalability
Solution Approach 2:
The SATA host interface circuit provides multi-functionality by enabling SATA hosts to connect to both direct-attached SATA target devices and remotely connected SATA target devices through the SAS fabric, making the system adaptable to different configuration scenarios while maintaining cost-effectiveness
2Adaptability or versatility
If STP initiators are used to connect SATA target devices to SAS fabric, then SAS fabric flexibility and scalability are achieved, but the initiators become more complex and costly
Solution Approach 1:
The SATA host interface circuit acts as an intermediary that handles protocol translation and SAS fabric communication, allowing the use of simpler SATA hosts instead of complex STP initiators. The interface circuit performs the functions previously requiring STP initiator capabilities
Solution Approach 2:
The SATA host interface circuit copies or emulates the functionality of STP initiators at the interface level, allowing standard SATA hosts to interact with the SAS fabric as if they were STP initiators, thereby reducing complexity while maintaining functionality
3Adaptability or versatility
If port multipliers are used in SATA architecture to extend connections, then some expansion is achieved, but the architecture still lacks the flexibility and scalability of SAS switched fabric
Solution Approach 1:
The SATA host interface circuit serves as an intermediary that bridges SATA architecture with SAS switched fabric, enabling expansion beyond what SATA port multipliers can achieve. This interface allows connection to multiple SATA target devices through the scalable SAS fabric infrastructure
Data Source
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AI summary
Methods and structure for directly coupling SATA hosts (SATA initiators) with SATA target devices through a SAS fabric and an enhanced SAS expander supporting such direct couplings. The enhanced SAS expander comprises SATA/STP connection logic to open a SAS (STP) connection between a directly attached SATA host and a SATA target device in response to receipt of an FIS from the host or target while no connection is presently open. The opened connection is closed after expiration of a predetermined timeout period of inactivity between the connected host and target. Thus, simpler, less costly SATA hosts and SATA target devices may be utilized while gaining the advantage of SAS architecture flexibility in configuration and scalability. SATA hosts may be coupled through the SAS fabric with a larger number of SATA target devices and multiple SATA hosts may be coupled with the SAS fabric.