Scatter Gather List Length Parameter Generation
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Solution Overview
Problem
In conventional multicasting environments, managing Scatter Gather Lists (SGLs) with different definitions leads to increased memory requirements, as each SGL needs separate context space, which becomes inefficient as the number of devices increases.
Innovation Solution
A method to generate various length parameters for multiple SGLs based on the length fields of another SGL, allowing for reduced memory usage by deriving length parameters dynamically, without modifying existing systems or firmware, and seamlessly integrating with existing hardware and software components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate context space is provided for all SGL fields in a multicasting environment, then each SGL can be independently defined, but memory requirements increase significantly
Solution Approach 1:
The patent implements a universal context memory structure where a single set of fields can serve multiple SGLs through multicasting. The context memory contains fields that are shared across multiple SGL definitions, allowing the same memory space to be universally applied to different device types and SGL configurations, thereby reducing overall memory requirements while maintaining adaptability.
Solution Approach 2:
The patent uses copying by deriving SGL length parameters for multiple SGLs from a single source SGL length field. Instead of storing separate length fields for each SGL, the system copies the length information from one SGL definition and applies it to generate parameters for other SGLs in the multicast group, significantly reducing the quantity of stored data while preserving the ability to define different SGL types.
2Adaptability or versatility
If context memory provides separate fields for all SGL definitions, then all SGL types can be supported, but the device complexity increases
Solution Approach 1:
The context memory is designed as a universal structure that can handle multiple SGL definitions through a single set of fields. By making the context memory multi-functional, it can serve different device types (SCSI, Fibre Channel, SAS, FCP) without requiring separate dedicated fields for each device type, thereby reducing structural complexity while maintaining broad support.
Solution Approach 2:
The patent merges the context memory fields into a unified structure that is shared across multiple SGLs. Instead of having separate, redundant fields for each SGL definition, the system combines the field structures so that a single context memory location serves multiple purposes, reducing the overall complexity of the memory architecture.
3Quantity of substance
If a single field describes all SGLs in context memory, then memory usage is reduced, but the system cannot handle SGLs with different definitions
Solution Approach 1:
The patent implements dynamic parameter generation where SGL length parameters are not statically defined for each SGL but are dynamically derived at runtime. The system uses a single source length field and dynamically generates the appropriate length parameters for each SGL in the multicast group based on the specific SGL definition being accessed, allowing memory efficiency while handling diverse SGL types.
Solution Approach 2:
The system changes parameters dynamically by deriving different SGL length parameters from a single source length field. Instead of having fixed, separate length fields for each SGL type, the system transforms the single source length parameter into the appropriate form for each target SGL based on the device type and SGL definition, enabling memory reduction while maintaining adaptability to various SGL definitions.
Data Source
AI summary
A method of generating length parameters, comprising the steps of reading a data stream from a host, detecting a particular field of the data stream, and calculating a variable based on a length parameter of a first list to be transferred. The data stream may comprise a plurality of definitions. The method may also comprise the step of selecting one of the list definitions. One of the list definitions may be used to generate a length parameter used in a second list in response to (i) the particular field of the data stream and (ii) the length parameter of the first list.