VxWorks

Installation

The VxWorks version of Jamaica is installed as described in the section "Installation". In addition, the following steps are necessary:

  /opt/WindRiver/wrenv.sh -p vxworks-6.2
  

Loading an application

An application created with the Jamaica Builder can be loaded on the VxWorks target like any other VxWorks program. If the target system is configured for disk, FTP or NFS access, simply enter the following command on the target shell:

  ld < <filename>
  

<filename> is the complete filename of the created application.

If you use real time processes (aka RTP), no seperate loading is needed. Loading and starting an RTP application is performed by just one command. Please proceede to next section to learn how to start an RTP application.

Starting an application

The main entry point for an application built with the Jamaica Builder is the name specified by the Builder option destination with the prefix "jvm_". The name "jvm" can also be used. If the option destination is not specified, the name of the class file containing the main() method is used. For example, in the VxWorks target shell the application can be started with:

  sp jvm_HelloWorld,<argument string>
  

Note: Even if the Builder generates a file with the specified name, it can be renamed later, because the name of the main entry point is read from the symbol table included in the object file.

Optional parameters, like classpath or Xbootclasspath, can be passed to the application as a single C argument string with text enclosed in """ (double quotes). Multiple arguments in the string can be separated by spaces. The start code of the created application parses this string and passes it as a standard Java string array to the main method.

If you are using VxWorks new feature of "real time processes" (aka RTP), please use the following shell command to start your RTP application:

  rtpSp "<Filename>"
  

If you want to specify command line parameters, add them as space seperated list in the following fashion:

  rtpSp "<Filename> <arg1> <arg2> <arg3>"
  

Linking the application to the VxWorks kernel image

The built application can also be linked directly to the VxWorks kernel image, for example for saving the kernel and the application in a FLASH memory. In the VxWorks kernel a user application can be invoked enabling the VxWorks configuration define INCLUDE_USER_APPL and defining the macro USER_APPL_INIT when compiling the kernel (see VxWorks documentation and the file usrConfig.c). The prototype to invoke the application created with the Builder is:

  int jvm_<main class name>(const char *commandLine);
  

where <main class name> is the name of the main class or the name specified via the Builder option destination. To link the application with the VxWorks kernel image the macro USER_APPL_INIT should be set to something like this name:

  extern int jvm_HelloWorld(const char *); jvm_HelloWorld(<args>)
  

where <args> is the command line (as a C string) which should be passed to the application.

Limitations

The current release of Jamaica for the VxWorks OS contains the following limitations:

• java.net.Socket.setSoTime() and java.net.Socket.getSoTime() are not implemented

• java.lang.Runtime.exec() is not implemented

• The following realtime signals are not available:

  • SIGSTKFLT

    SIGURG

    SIGXCPU

    SIGXFSZ

    SIGVTALRM

    SIGPROF

    SIGWINCH

    SIGIO

    SIGPWR

    SIGSYS

    SIGIOT

    SIGUNUSED

    SIGPOLL

    SIGCLD

• Jamaica does not allow an application to set the resolution of the clock in javax.realtime.RealtimeClock. The resolution of the clock depends on the frequency of the system ticker (see sysClkRateGet() and sysClkRateSet()). If a higher resolution for the realtime clock is needed the frequency of the system ticker must be increased. Care must be taken when doing this, because other programs running on the system may change their behavior and even fail. In addition, under VxWorks 5.4 the realtime clock must be informed about changes of the system ticker rate with the function clock_setres(). The easiest way to do this is to add the following into a startup script for VxWorks:

  sysClkRateSet(1000) timeSpec=malloc(8) (*(timeSpec+0))=0 (*(timeSpec+4))=1000000 clock_setres(0,timeSpec) free(timeSpec)

  This example sets the system ticker frequency to 1000 ticks per second and the resolution of the realtime clock to 1ms.

• java.net.Socket.getSoTimeout() is not implemented and does not report an error if called. java.net.Socket.setSoTimeout() is not implemented and does not report an error if called.

Special notes

• Object files: because applications for VxWorks are usually only partially linked, missing external functions and missing object files cannot be detected at build time. If native code is included in the application with the option object, Jamaica cannot check at build time if all needed native code is linked to the application. This is only possible in the final linker step when the application is loaded on the target system.