1. VxWorks

2. What is VxWorks?
VxWorks, from Wind River Systems, is a networked real-time operating system designed to be used in a distributed environment. It runs on a wide variety of hardware. It requires a host workstation for program development; supported host platforms include Sun3, Sun4….
Is the run-time component of the Tornado 3 embedded development platform.

3. What is VxWorks?
The VxWorks RTOS comprises the core capabilities of the wind microkernel (not monolithic) along with advanced networking support, powerful file system and I/O management, and C++ and other standard run-time support.

5. What is VxWorks?
The development environment is based on cross-development or remote-development method. You will need a UNIX machine of some sort (e.g. SUN's) to run the compilers and debuggers. The compiled application code can be downloaded to the target and runs as part of the VxWorks image. During the development phase or thereafter, individual object code (.o files) can be downloaded dynamically to running target system. Finished applications can be ROM'ed or whatever.

6. What is VxWorks?
VxWorks most definitely is not a "realtime UNIX", or a varient of UNIX as often misunderstood by some people. The confusion perhaps is due to the fact that UNIX hosts are used most widely to develop applications for VxWorks (and VxWorks itself).

7. Brief History of VxWorks
WRS was started by Jerry Fiddler and David Wilner in Jerry's garage as a contract/consultant shop for realtime, embedded systems and other fun things. They wrote a bunch of neat programs for their work and eventually adding some things unheard of in embedded/realtime market in those days such TCP/IP networking. And continued to pioneer in this area by adding NFS, etc.

8. Brief History of VxWorks
VxWorks was the name given the collection of software which ran on top of various realtime kernels including VRTX and pSOS as well an earlier slower version of WIND kernel. VxWorks now no longer runs on other kernels; it now runs exclusively on its own WIND kernel since the 5.0 release, for which the WIND was rewritten by John Fogelin.

9. Wind microkernel Efficient task management
multitasking, unlimited number of tasks
Preemptive and round-robin scheduling
Fast, deterministic context switching
256 priority levels

10. Wind microkernel Fast, flexible intertask communications
Binary, counting, and mutual exclusion semaphores with priority inheritance
Message queues – local and locale-transparent distributed messaging
POSIX pipes, counting semaphores, message queues, signals and scheduling
Control sockets
Shared memory
Standard COM
VxFusion

11. Wind semaphores binary mutual exclusion Counting
The fastest, most general purpose semaphore. Optimized for synchronization and can also be used for mutual exclusion.
mutual exclusion
A special binary semaphore optimized for problems inherent in mutual exclusion: priority inheritance, deletion safety and recursion.
Counting
Like the binary semaphore, but keeps track of the number of times the semaphore is given. Optimized for guarding multiple instances of a resource.

12. Wind microkernel High scalability
Incremental linking and loading of components
Fast, efficient interrupt and exception handling
Optimized floating-point support
Dynamic memory management
System clock and timing facilities

13. Networking support BSD 4.4 TCP/IP networking
IP, IGMP, CIDR, TCP, UDP, ARP
PPP, SLIP/CSLIP
Standard Berkeley sockets
Berkeley packet filter
RIPv1/v2 and routing sockets
TFTP, rlogin, telnet, rsh
NFS dient and server, ONC RPC
SNTP
SNMPv1/v2c/v3
Network Protocol Toolkit
BGP-4
Ipsec/IKE
NAT
L2TP
MPLS
ATM
Frame relay
ISDN
SS7

14. Fast, flexible I/O and local file system
POSIX asynchronous I/O and directory handling
SCSI support
MS-DOS-compatible file system
TrueFFS flash file system (optional)
ISO 9660 CD-ROM file system
PCMCIA support

15. Other Features Protection domain management
Resource tracking and management
System overrun protection
Powerful loader facilities

16. Protection domain management

17. Overlapped memory model

18. Multasking ready – pending – delayed – suspended –
the task is waiting only for CPU time
pending –
the task is blocked because some resource is unavailable
delayed –
the task is inactive for a pre-determined time interval
suspended –
the task is prevented from becoming active

19. Multasking The highest-priority ready task is executing. delayed
pending
ready
suspended
taskInit()

20. Priority Preemption

21. Round-Robin Scheduling

22. differences between traditional UNIX and VxWorks
VxWorks runs in one mode. No protected vs. user mode switching is done. Running in supervisor mode on most processors, and not using traps for system calls, VxWorks can achieve minimal overhead on a given piece of hardware than UNIX. Programming on VxWorks can be more tricky than UNIX for the same reason.
UNIX provides resource reclamation; by default, VxWorks does not.
VxWorks does not have full "process"; it only has tasks, or "threads".

23. differences between traditional UNIX and VxWorks
VxWorks: minimal interrupt latency (e.g. spl's are quasi-implemented as semaphores). Traditional UNIX: high interrupt latency (e.g. spl's are implemented as interrupt lock and unlock calls).
VxWorks: priority interrupt-driven preemption, optional round-robin time-slicing. Traditional UNIX: prioritized round-robin preemptive time-slicing. Since VxWorks is just a glorified "program" it can be changed and customized pretty easily. Task scheduling can be customized as desired.
VxWorks networking code, however, is very UNIX compatible. It is essentially "ported" version of BSD UNIX TCP/IP code -- tahoe release .

24. Example: Porting VxWorks to Gmicro/200
Portable kernel modifications
Establishing the VxWorks shell environment
Adding Gmicro-specific debug functions
Adding board-specific functions
Adding networking support
Building BootROM
Optimizing and tuning
testing

25. Impl. Architecture

26. development Tornado in Mobile Internet
Wind River rolls out safety-critical software