TinyOS v.3 + Updates

TinyOS is a very small operating system, built on top of a simple-minded virtual machine, whose purpose is purely educational. It is not related in any way to the well-known operating system for wireless sensors, but since it was first conceived in 2003, there was a name collision that I have not yet resolved. This code (in its long history) has been used for many years to teach the Operating Systems course at the Technical University of Crete.

In its current incarnation, tinyos supports a multicore preemptive scheduler, serial terminal devices, and a unix like process model. It does not support (yet) memory management, block devices, or network devices. These extensions are planned for the future.

Quick start

$ git clone https://github.com/vsamtuc/tinyos3.git
$ cd tinyos3
$ touch .depend

After downloading the code, just build it.

$ make

and try to discover system and test files.

If all goes well, the code should build without warnings.

Test

Some terminal tests for Linux Ubuntu

$ gnome-terminal -e "./terminal 0"
$ gnome-terminal -e "./terminal 1"
$ ./test_bios2
$ ./bios_example5

You can run your first instance of tinyos, a simulation of Dijkstra's Dining Philosophers.

$ ./mtask 1 0 5 5
FMIN = 27    FMAX = 37
*** Booting TinyOS
[T] .  .  .  .      0 has arrived
[E] .  .  .  .      0 is eating
[T] .  .  .  .      0 is thinking
[E] .  .  .  .      0 is eating
 E [T] .  .  .      1 has arrived
 E [H] .  .  .      1 waits hungry
 E  H [T] .  .      2 has arrived
< more lines deleted >

Then, you are ready to start reading the documentation (you will need doxygen to build it)

make doc

Point your browser at file doc/html/index.html. Happy reading!

Build dependencies

Tinyos is developed, and will probably only run on Linux (its bios.c file uses Linux-specific system calls, in particular signal streams). Any recent (last few years) version of Linux should be sufficient.

Working with the code, at the basic level, requires a recent GCC compiler (with support for C11). The standard packages doxygen and valgrind with their dependencies (e.g., graphviz) are also needed for anything serious, as well as the GDB debugger.

Upgrades

Feedback Queue

• Multilevel Feedback Queues (changes to initial kernel_sched.c)
  • Αrray of queues, a queue for each priority.
  • Priotity => TCB of an integer field
  • Quantum ends => Scheduler calculates a new value for that field, which is actually the queue to which the thread will be added.
  • First element of first non-empty queue is the next thread.
• Multithreading processess (syscall changes to initial kernel_thread.c)
  • PTCB <> TCB
  • CreateThread
  • ThreadSelf
  • ThreadJoin
  • ThreadExit
  • TreadDetach

Pipes, Sockets

• Process communication mechanisms, pipes and sockets. (syscall changes to initial kernel_socket, kernel_pipe.c, kernel_steams.c)

  • Socket
  • Connect
  • Listen
  • Accept
  • Shutdown

• User program for standard output information about the system (syscall changes to initial kernel_proc).

Pipes, Sockets folder has all upgrades (includ. scheduling). For more informations ¹², check doc folder.

Acknowledgements

• This project was implemented for the requirements of the lesson Operating Systems
• Many credits to professor Vsam

Footnotes

1. Feedback Queue has Feedback Queues and Threads ↩

2. Pipes, Sockets has all upgrades (server communication and scheduling). ↩