Memory Command Sequencing With Sequential Identifiers After Power Loss
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Solution Overview
Problem
Existing memory systems face challenges in maintaining the correct command order during asynchronous power loss events, leading to potential file structure corruption and data loss due to inefficient synchronization commands or incomplete implementation of barrier commands.
Innovation Solution
Incorporating a sequential identifier in each command to maintain the original order, allowing the host and memory systems to determine the latest valid command and invalidate subsequent commands, thereby ensuring data integrity during power loss events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barrier commands are used to maintain command order, then command execution order is preserved, but implementation completeness is insufficient leading to data corruption
Solution Approach 1:
The patent applies preliminary action by inserting sequential identifiers into commands before transmission to the memory device. This allows the host system to track and validate command execution order in advance, rather than relying solely on barrier commands that may not be fully implemented. The sequential identifiers are prepared and attached to commands beforehand, enabling post-transmission verification of command order integrity.
Solution Approach 2:
The patent implements feedback mechanisms where the host system receives acknowledgments from the memory device regarding command execution status. By comparing the sequential identifiers of transmitted commands with the acknowledged execution order, the host can detect discrepancies and identify the latest valid command. This feedback loop ensures that even if barrier commands are not fully implemented, the system can verify and correct command order issues.
2Reliability
If synchronization commands are used to maintain command order, then data integrity is improved, but system efficiency decreases due to command reordering
Solution Approach 1:
The patent applies preliminary action by pre-inserting sequential identifiers into commands before they are transmitted to the memory device. This eliminates the need for post-transmission reordering operations, as the original command sequence is already marked and trackable. The host system can directly compare sequential identifiers with execution acknowledgments to determine the latest valid command, avoiding inefficient reordering processes.
Solution Approach 2:
The patent extracts the command sequencing function from the barrier command mechanism and implements it independently through sequential identifiers embedded in each command. This separation allows the system to maintain command order information without relying on barrier commands that cause reordering, thereby improving system efficiency while preserving data integrity.
3Measurement precision
If sequential identifiers are inserted in each command, then command order tracking is improved, but device complexity increases
Solution Approach 1:
The patent merges the sequential identifier with the existing command structure by embedding the identifier within the command packet itself. Rather than creating separate tracking structures or additional communication protocols, the sequential information is combined with the command data, reducing overall system complexity while maintaining precise command order tracking capability.
Data Source
AI summary
Methods, systems, and devices for techniques for controlling command order are described. An entity of a host system, such as a file system, may insert a sequential identifier into commands generated by the entity to indicate an order of the commands. In some examples, the host system may specify a set of commands in a first sequence to be transmitted to the memory system. The host system may subsequently reorder the set of commands in to a second sequence and transmit the set of commands to the memory system. In some cases, following a power-on condition, the memory system may determine a latest valid command of the set of commands. The memory system may subsequently invalidate one or more logical addresses associated with commands having sequence identifiers after the sequence identifier of the latest valid command.