How_to_Code_on_TinyOS

Resources
Gaurav’s TinyOS-1.x installation howto: /~gmathur/misc/tinyos_set up.htm Tinyos-2.x installation howto (straightforward): /tinyos-2.x/doc/html/installtinyos.html The official TinyOS tutorial (pretty good): /tinyos-1.x/doc/tutorial/ The offical TinyOS-2.x tutorial (very good): /tinyos2.x/doc/html/tutorial/index.html nesC: /
HOW TO CODE ON TINYOS
Outlines
What is TinyOS? Hardware & Software NesC A simple example Conclusion
SO WHY DO WE NEED A NEW OS?
TRADITIONAL OS
Huge ! Multi-threaded architecture =>large memory I/O model Kernel and user space separation Typically no energy constraints Ample available resources
TinyOS & nesC Concepts
New Language: nesC. Basic unit of code = Component Component Process Commands Throws Events Has a Frame for storing local state Uses Tasks for concurrency Components provide interfaces Used by other components to communicate with this component
Resources
Other Docs: nesC paper: /~gmathur/tinyos /nesc-pldi-2003.pdf nesC manual: /~gmathur/tinyos /nesc-ref.pdf TinyOS abstractions: /~gmathur/tinyos /tinyosnsdi04.pdf
nesC Keywords
nesC Keywords implementation
Interfaces
Modules
Implement one or more interfaces Can use one or more other interfaces
Modules (Sample)
Configurations
Commands Should be non-blocking i.e. take parameters start the processing and return to app; postpone time-consuming work by posting a task Can call commands on other components Events Can call commands, signal other events, post tasks but cannot be signal-ed by commands Pre-empt tasks, not vice-versa Tasks FIFO scheduling Non pre-emptable by other task, pre-emtable by events Used to perform computationally intensive work Can be posted by commands and/or events
Simple Example 1
Blink Application
Blink.nc configuration
Simple Example 1
Blink Application
BlinkM.nc module
Simple Example 2
Communication between two sensors Environment : Wubuntu + TinyOS 2.0 Hardware: TelosB sensors
nesC
Naming conventions nesC files extension: .nc Clock.nc : either an interface (or a configuration) ClockC.nc : a configuration ClockM.nc : a module
Desired OS Properties
Small memory footprint Efficient in power and computation Communication is fundamental Real-time Support diverse application design
The Hardware
Software
TinyOS (Platform) Coding language
NesC (Network Embedded System C)
TinyOS Memory Model
STATIC memory allocation! No heap (malloc) No function pointers No dynamic, run-time allocation Global variables Available on a per-frame basis Conserve memory Use pointers Local variables Saved on the stack Declared within a method
TinyOS Solution
Concurrency: uses event-driven architecture Modularity Application composed of components OS + Application compiles into single executable Communication Uses event/command model FIFO and non pre-emptive scheduling No kernel/application boundary
Байду номын сангаас
Components
Two type of components
Module
component written with code
Configuration
components wired together
Components
TinyOS Application (Sample)
Commands/Events/Tasks
Two components are linked together in nesC by wiring them Interfaces on user component are wired to the same interface on the provider component 3 wiring statements in nesC: endpoint1 = endpoint2 endpoint1 -> endpoint2 endpoint1 <- endpoint2 (equivalent: endpoint2 -> endpoint1)
Reference
nesC paper: /~gmathur/tinyos/ne sc-pldi-2003.pdf
Sensor Hardware Constraints
Lower Power Limited memory Slow CPU Size (Small) Limited hardware parallelisms Communication using radio Low-bandwidth Short range
Configurations (Sample)
nesC Wiring Syntax
Compile & Run
Compiler processes nesC files converting them into a gigantic C file Has both your application & the relevant OS components you are using Then platform specific compiler compiles this C file Becomes a single executable Loader installs the code onto the Mote (Mica2, Telos, etc.)