Direct Power-Off Transition from Suspended State in Data Processing
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Solution Overview
Problem
Image forming apparatuses face inefficiencies in quickly transitioning from a suspended state to a power-off state and back to a standby state, leading to prolonged activation times and potential logical faults in auxiliary storage devices.
Innovation Solution
A data processing apparatus with a detection unit for shifting to a suspended state, a control unit for direct power-off from the suspended state without returning to standby, and an activation unit for restoring memory content upon power-on, utilizing non-volatile storage to save and restore data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the image forming apparatus returns to standby state before power-off from suspended state, then shutdown processing can be completed, but the transition time is prolonged
Solution Approach 1:
The patent extracts the essential function of shutdown processing (saving memory content to non-volatile storage) and separates it from the standby state transition. By directly transitioning from suspended state to power-off state without returning to standby, the invention removes the time-consuming intermediate step while preserving the critical data saving function through the detection unit and shift unit.
2Speed
If direct power-off from suspended state is implemented, then transition speed is improved, but inconsistency check is required upon power-on
Solution Approach 1:
The detection unit performs preliminary detection of the power-off instruction in the suspended state, and the shift unit executes the memory content saving operation before the actual power-off occurs. This preliminary action ensures that data consistency is maintained without requiring lengthy inconsistency checks after power-on, as the critical data saving was completed in advance.
3Reliability
If flush processing for caches is executed during shutdown, then data consistency is ensured, but activation time after power-off becomes very long
Solution Approach 1:
The shift unit executes the cache flush processing as a preliminary action before the power-off state is reached. By completing the flush processing for caches in advance during the transition from suspended to power-off state, the system ensures data consistency without requiring extensive flush operations after power-on, thereby significantly reducing activation time.
Data Source
AI summary
When a data processing apparatus according to this invention detects generation of an event to shift from the standby state to the suspended state, it saves the contents of a memory in the standby state in a non-volatile storage device in response to detection of generation of the event, and shifts to the suspended state. When power-off is instructed in the suspended state, the data processing apparatus shifts from the suspended state to the power-off state without the mediacy of the standby state.