Operating Systems

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QUESTIONS	XPRESS	TG X-Stack	DEGAS	D-TEC	DynAX	X-TUNE	GVR	CORVETTE	SLEEC	PIPER
PI	Ron Brightwell	Shekhar Borkar	Katherine Yelick	Daniel Quinlan	Guang Gao	Mary Hall	Andrew Chien	Koushik Sen	Milind Kulkarni	Martin Schulz
What are the key system calls / features that you need OS/R to support? Examples: exit, read, write, open, close, link, unlink, chdir, time, chmod, clone, uname, execv, etc.	(EXPRESS)	(TG)	(DEGAS)	(D-TEC)	(DynAX)	(X-TUNE)	(GVR)	(CORVETTE)	SLEEC	sockets, ptrace access, dynamic linking, timer interrupts/signals, access to hardware counters, file I/O
Does your project implement it's own lightweight thread package, or does it rely on the threads provided by the OS/R? If you implement your own threads, what are the key features that required developing a new implementation? If you don't implement your own thread package, what are the key performance characteristics and APIs needed to support your project?	(EXPRESS)	(TG)	(DEGAS)	(D-TEC)	(DynAX)	(X-TUNE)	(GVR)	(CORVETTE)	N/A	relying on native threads, typically pthreads, which is appropriate
Do you currently view virtualization as a key requirement to support your x-stack project? If so, why?	(EXPRESS)	(TG)	(DEGAS)	(D-TEC)	(DynAX)	(X-TUNE)	(GVR)	(CORVETTE)	N/A	No
What energy/power and reliability APIs do you expect from the OS/R?	(EXPRESS)	(TG)	(DEGAS)	(D-TEC)	(DynAX)	(X-TUNE)	(GVR)	(CORVETTE)	N/A	Power: Power measurements at varying granularity using processor internal counters and external sensors, for autotuning access to setting DVFS levels or power capping; Resilience: access to fault notification (for corrected and non-corrected errors)
Please describe how parallel programs are "composed" within your project, and what APIs and support is required from the OS/R?	(EXPRESS)	(TG)	(DEGAS)	(D-TEC)	(DynAX)	(X-TUNE)	(GVR)	(CORVETTE)	N/A	N/A
What is your model for extreme-scale I/O, and how do you expect the OS/R to support your plans?	(EXPRESS)	(TG)	(DEGAS)	(D-TEC)	(DynAX)	(X-TUNE)	(GVR)	(CORVETTE)	N/A	For PIPER this refers to performance information: hierarchical aggregation through MRNet to reduce data and perform online analysis. OS support required for bootstrapping / optionally, could be integrated with OS backplanes
Does your project include support for multiple, hierarchical, memory regions? If so, how will it be allocated and managed, by your xstack project or my the OS/R? What APIs do you expect the OS/R to support complex and deep memory?	(EXPRESS)	(TG)	(DEGAS)	(D-TEC)	(DynAX)	(X-TUNE)	(GVR)	(CORVETTE)	N/A	N/A