Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

System IntegrationSystem Integration

Raj RajkumarProfessor, ECE and CS

Director, Real-Time and Multimedia Systems LabCo-Director, GM-CMU Collaborative Research Lab

Carnegie Mellon Universityhttp://www.ece.cmu.edu/~raj

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

BackgroundBackground

• Real-Time operating systems and networking– Real-time Linux + nano-RTOS

• Scheduling theory

4

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

Example: Automotive ControlExample: Automotive Control

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

Example: Wearable SensorsExample: Wearable Sensors• Acceleration, Tilt, Ambient Light,

Temperature and Audio• Tactile, Visual and Audio Notification• Bluetooth and IR Communication• ARM7 Processor• 1Mb Flash Storage• Extensive Power Management

• Frequency Scaling• Peripheral Power gating

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

The “Software Problem”The “Software Problem”

• There is no software problem! – I must be low on sugar…

• We do have a “system problem”– The same software in different contexts may be

acceptable or not• Depends on the system’s needs

– The cost of development and verification

– The cost of failure

– The cost that the customer is willing to bear

• Depends on your system– How is it different from the other system?

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

The TemptationThe Temptation

• The software has been used before without problems– Therefore, it should work again in my system.

Ariane 5 launch

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

The GreedThe Greed

• Generation n+1 will have different problems than Generation 1.

“Unintended” feature interaction Feature creep

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

It’s binary, right?It’s binary, right?

• Multiple levels of operation– Without failures– With failures

• One or more failures • Which failures

• Optimal operation (e.g. sampling frequency)?– No: depends on environment and where we are

• Minimize energy?– No: control energy

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Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

Solutions Solutions

• Decouple wherever possible– Separate functional correctness from

• Timing correctness• Replication for fault-tolerance• Security

– Multiple models at different abstractions

• Capture couplings where they must be– Capture interactions and dependencies– Manage couplings automatically– Generate code

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

Software InfrastructureSoftware Infrastructure• Predictable real-time operating systems

Windows

• We can analyze and validate timing behavior• Wired and wireless networking

• Multi-hop wireless networking to extend reach

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

ChallengesChallenges• “Barium” injection to see problems and locations

– Testing must think like the car thief and explore/exploit openings

– Reverse reasoning from good/bad outcome(s) to source(s)

• Model different aspects of system behavior

• Know thy system!

Model(s)

AnalyzeAnalyze

GenerateGenerate

Real-Time and Multimedia Systems Laboratory

Carnegie Mellon

BioBioDr. Ragunathan (Raj) Rajkumar is a Professor in the Departments of Electrical & Computer Engineering, and of Computer Science at Carnegie Mellon University where he serves as the Director of the Real-Time and Multimedia Systems Laboratory and the Co-Director of the General Motors-CMU Collaborative Research Laboratory. Raj obtained his M.S. and Ph.D. degrees from Carnegie Mellon University in 1986 and 1989, respectively. He has been conducting research in distributed real-time and embedded systems for over 18 years. Since 1985, his work has focused on all system aspects of real-time and multimedia systems including operating systems, networking, and middleware services. His work on priority inheritance protocols to avoid priority inversion problems is well known in the research and practitioner communities. He served as the Program Chair and General Chair of the 1997/1998 IEEE Real-time Technology and Applications Symposia (RTAS ’97 and ’98), respectively. He was the Program Chair of the SPIE/ACM Symposium on Multimedia Computing and Networking (MMCN ’03). He is currently serving as the Program Chair of the 2003 IEEE Real-Time Systems Symposium (RTSS 2003) and the General Chair of the 2004 SPIE/ACM Symposium on Multimedia Computing and Networking (MMCN 2004). He has also authored the book titled “Synchronization in Real-Time Systems: The Priority Inheritance Approach”, and edited a book titled “Real-Time Operating Systems and Services”. He also is a member of the Steering Committee of the EmSoft Working Group focusing on software technologies for embedded systems. He holds one U.S. patent and has authored over 75 papers in the domain of real-time and embedded systems. His research interests include real-time and multimedia operating systems, real-time scheduling theory, end-to-end resource management, and systems support for networking. He serves on the Technical Advisory Board and is a consultant to many companies in the embedded real-time systems domain. Dr. Rajkumar is also a Founder of TimeSys Corporation (www.timesys.com), a popular vendor of embedded real-time versions of Linux and Java.