1. 1. COMPONENT BASED EMBEDDED SYSTEMS ANJALI SEJWAL 2K11/SE/007 CHARU MEHNDIRATTA 2K11/SE/025 NIKITA JAIN 2K11/SE/045 SONALI DEV 2K11/SE/076 SUNITA TANDON 2K11/SE/077
2. 2. INTRODUCTION What is Component Based Technology? It deals with the idea of breaking large, complex software applications into a series of pre-built and easily developed, understood, and changeable software modules. It facilitates cheap and quick delivery of software solutions. What is Embedded System? A computer system that is part of a larger system and performs some of the requirements of that system; for example, a computer system used in an aircraft or rapid transit system.
3. 3. What is Embedded System? An embedded system is a computer system with a dedicated function within a larger mechanical or electrical system, often with real-time computing constraints For example, a computer system used in an aircraft or rapid transit system. Embedded systems range from portable devices such as digital watches and MP3 players, to large stationary installations like traffic lights, factory controllers, and largely complex systems like hybrid vehicles, MRI, and avionics.
4. 4. What is Embedded System? Properties typical of embedded computers Low power consumption, Small size, Rugged operating ranges Low per-unit cost User interface Processors in embedded systems Ready made computer boards
5. 5. NEED FOR COMPONENT BASED EMBEDDED SYSTEMS Huge market arises for embedded devices, and thus for software for them Similar basic functionalities are repeated New functionalities specific to the devices are added constantly Shorter development time is required Better quality is expected
6. 6. SOLUTION TO THESE PROBLEMS? SOFTWARE COMPONENTS EMBEDDED DEVICE COMBININGCBT & EMBEDDED SYSTEM TECHNOLOGY
7. 7. Embedded vs. Component Based Approach EMBEDDED Monolithic approach requires re-implementing the functionalities Embedded devices are too small for component off-the-shelf technologies Run-time composition COMPONENT BASED Component based SE provides a mean to reuse the functionalities Component based SE can provide a framework instead of technology Configuration composition
8. 8. Embedded vs. Component Based Approach contd.. EMBEDDED Coarse-grained components Black-box reuse Binary independence COMPONENT BASED Fine-grained components White-box reuse or Gray-box reuse (glass- box) Source level portability
9. 9. Embeddedsystems Essence of embedded systems
10. 10. Widely used component models for embedded systems Direct use of component models CORBA (telecommunication) COM/DCOM, .NET process industry Improved component-models (with added functionalities) OPC (OLE process control Foundation) Restricted (use of) component-models to achieve predictability Using only specification (IDL) , no multiple interface, etc.
11. 11. Embedded systems Small Embedded systems Large Embedded systems Power, money Reliability, robustness
12. 12. Specific requirements of embedded systems Real-time requirements Resource consumption CPU, Memory, Power, Physical space Dependability Safety, reliability, availability Life-cycle properties (long life systems) Maintainability, expandability Portability Increasing interoperability
13. 13. Real-time Properties Related to time Includes response time, execution time, deadline, latency time.
14. 14. Dependability defined as an ability of a system to deliver service that can justifiably be trusted and an ability of a system to avoid failures. Attributes of Dependability Reliability Availability Integrity Confidentiality
15. 15. Resource Consumption Depends on size of system and production costs. Includes factors -CPU -Memory -Power -Physical space
16. 16. Life Cycle Properties For long time systems Maintainability, expandability Portability
17. 17. State of the practice & experience for Embedded Systems Embedded systems comprise a scale from ultra small devices with simple functionality, through small systems with sophisticated functions, to large, possibly distributed systems, where the management of the complexity is the main challenge. A common characteristic of all systems is increasing importance of software. For example, software development costs for industrial robots make today about 75% of total costs, while in car industry it is today about 30%. Some ten, fifteen years ago this number was about 25% for robots and neglect able for cars. A second common characteristic is increasing interoperability.
18. 18. AutomotiveIndustry Within the automotive industry, the component-based approach has a relatively long tradition, as these systems are typically built from system components that are either developed in-house or provided by external suppliers the entire control system of an advanced car includes a number of Electronic Control Units (ECUs) equipped with software that implements vehicle functions. ECUs are treated as system components that can be developed and build independently of each other and of the entire system The ECUs are connected to the system (the car) through sensors and actuators and between themselves via one or several buses. Usually the buses are integrations points and their protocols specify the communications between the ECUs.
19. 19. IndustrialAutomation Typical application domains of industrial automation are in control of industrial processes, power supply, industrial robots. Industrial automation domain comprises a large area of control, monitoring and optimization systems Most control systems are manufactured in rather large volumes, and must to a large extent be configurable to suit a variety of customer contexts.
20. 20. They can be classified according to different levels of control: i) Process level (for example, a valve in a water pipeline, a boiler, etc.) (ii) Field level that concerns sensors, actuators, drivers, etc (iii) Group control level that concerns controller devices and applications which control a group of related process level devices in a closed-loop fashion (iv) Process control level i.s. operator stations and processing systems with their applications for plant-wide remote supervision and control (v)Production or manufacturing management level that includes systems and applications for production planning.
21. 21. ConsumerElectronics Consumer electronics products, such as TV, VCR, and DVD, are developed and delivered in form of product families Production is organized into product lines - this allows many variations on a central product definition A product line is a top-down, planned, proactive approach to achieve reuse of software within a family or population of products. It is based on use of a common architecture and core functions included into the product platform and basic components
22. 22. Because of the requirements for low hardware and production costs, general-purpose component technologies have not been used, but rather more dedicated and simpler propriety models have been developed An example of such a component model is the Koala component model used at Philips . Koala is a component model and an architectural description language to build a large diversity of products from a repository of components. Koala is designed to build consumer products such as televisions, video recorders, CD and DVD players and recorders, and combinations of them.
23. 23. Otherdomains: Telecommunication, avionics and aerospace, transportation, computer games, home electronics, navigation systems, etc While there is many similarities between these domains there are also very different requirements for their functional and extra-functional properties The consequences are that the requirements for component -based technologies are different, and consequently we cannot expect to have one component model.
24. 24. Basic concepts for Component based Embedded Systems It includes the following features:- Contractually specified interfaces Component as a unit of composition and independent deployment Explicit context dependencies Component granularity Reuse Location transparency Component wiring Portability, platform independence
25. 25. Component-based approach for small embedded systems Contractually specified interfaces Contract addresses the functional requirements of the component. In embedded environment there is also another aspect non-functional requirements, like memory consumption, response time, processing power required, etc. All of them need to be addressed as part of the contract
26. 26. Interfaces The interfaces are usually implemented as object interfaces that supports Polymorphism Late Binding Address some semantic specification
27. 27. Explicit context dependencies Run-time environment CPU RTOS Resource constraints Component implementation language In embedded environment, the context is not only the components, which a given component depends on. It is also a run-time environment that it is executed in. Other components and interfaces required & provided interfaces (Contractual-based interfaces) Set of interfaces Component Technology Embedded system Specific
28. 28. Reuse Black-box reuse From components user point of view White-box reuse From composition environment point of view Gray-box reuse (glass-box) If clear conventions for knowledge about implementation are introduced Component Technology Component Technology
29. 29. Portability, Platform independence Binary independence Source level portability Design-time composition Run-time environment restrictions Source level portability requires Agreement on implementation language Agreement on available libraries Providing proper abstractions (i.e. RTOS API) Component Technology Component Technology
30. 30. Component-based approach for LARGE embedded systems Here the resource constraints are not the primary concerns. The complexity and interoperability play much more important role. Since the complexity the development of such system is very expensive and cutting the development costs is highly prioritized. For this reason general-purpose component technologies are of more interesting than in a case for small systems.
31. 31. Scope of improvements Direct use of component models CORBA (telecommunication) COM/DCOM, .NET process industry Improved component-models (with added functionalities) OPC (OLE process control Foundation) Restricted (use of) component-models to achieve predictability Using only specification (IDL) , no multiple interface, etc.
32. 32. The priorities of CBSE for embedded systems are: Predicting system properties. A research challenge today is to predict system properties from the component properties. This is interesting for system integration, to achieve predictability, etc. Development of widely adopted component models for real- time systems. Such a model should be supported by technology for generating necessary runtime infrastructure, generation of monitors to check conformance with contracts, etc.
33. 33. Thank you!