Processor Facility Emulation for Binary-Compatible LPAR Migration
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Solution Overview
Problem
Existing computer server hardware generations often have mutually exclusive facilities, requiring software modifications and recompilation to maintain binary compatibility, leading to additional licensing fees and time-consuming migrations.
Innovation Solution
A method is implemented in the operating system to detect facility availability and manage processor facility access, enabling seamless migration between hardware generations by disabling or emulating transactional memory (TM) as needed, without requiring software updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hardware facilities are made mutually exclusive between generations, then hardware design flexibility is improved, but binary compatibility deteriorates
Solution Approach 1:
The patent introduces an operating system as an intermediary layer between the application and the hardware facility. The OS contains a facility availability detector that checks whether a required facility exists on the target hardware, and a facility emulator that provides the missing facility functionality. This intermediary approach allows applications compiled for one hardware generation to run on another generation without recompilation, resolving the binary compatibility issue while maintaining hardware design flexibility.
2Productivity
If software modifications are required for hardware migration, then hardware facility optimization is improved, but migration time and cost deteriorate
Solution Approach 1:
The patent implements preliminary action by having the operating system detect facility availability and set up emulation mechanisms before the application actually needs to use the facility. When an application attempts to use a facility, the OS proactively checks if it's available on the current hardware and pre-configures the emulation environment if needed. This prevents runtime errors and eliminates the need for post-migration software modifications, reducing migration time while maintaining hardware optimization benefits.
3Reliability
If facility emulation is implemented, then binary compatibility is improved, but system complexity deteriorates
Solution Approach 1:
The patent extracts the facility emulation functionality from the hardware layer and places it entirely in the software layer (operating system). This separation means that the hardware remains simple and unchanged, while the OS handles all emulation complexity through software components. The facility emulator is implemented as software that intercepts facility calls and provides equivalent functionality through software routines, eliminating the need for complex hardware emulation circuits while maintaining binary compatibility.
Data Source
AI summary
Method, computer program product, and computer system are provided. A first migration of a running logical partition (LPAR) is performed from a first-generation computer to a second-generation computer. Availability of a facility differs between the first- and second-generation computers. Upon completion of the first migration, an operating system of the running LPAR detects whether a required facility in use on the first-generation computer is available on the second-generation computer. Operating system takes an action to continue an orderly execution of the LPAR, the operating system, and threads of an application in the LPAR depending on the availability of the required facility. A second migration is performed of the running LPAR from the second-generation computer back to the first-generation computer. The required facility is available on the first-generation computer. The operating system restores access to threads of the application to the required facility.