[Oberon] Please, what does it means? And how do deal with this?

[mcintosh at vima.austin.tx.us]

The intel '386 and higher processors have flags in the task selector descriptor
that control how the CPU works.  Some of the flags denote that a segment is a
data or code segment.  

If a segment is denoted as a data only segment, and a jmp, call, or rti instruction
attempts to send the CS:IP (program counter) to that segment, you will get a 
processor exception that would be described by what you are seeing.

In all of the Oberon systems that I have studied, the system does not allocate
a segment that is data only.

I am left with the thought that the version of Oberon that you are using has
dramatically departed from all its kindred, or else you are trying to load a
task selector that was not allocated under Oberon system control.

Again, I wonder about how the task was initialized that you are trying to use.
Does the system use the assembler?  Do you import the module SYSTEM?
Are you using a pointer that was never initialized and also using the compiler
flags that turn off the run-time checks?

Many of us have used Oberon with satisfaction for sophisticated real applications.


> > I still does not understand what does mean this enigmatic run-time mesage:
> > " Trap kind: Instruction-Fetch from No-Execute Segment" !?
> > As the code has any problem to compile...
> 
>  This mesage does mean: this "toy real-time operation system"
> does not have accomplished a task until  the deadline time
> especified!!!



Does this mean that you have changed some data and now the program does not
trap in the same place?

Again, are you writing directly to memory using something such as SYSTEM.PUT, and
bypassing the safety of the language?

> 
>  It was only a matter of adjust the parameters to execute the
> real-time task related with the problem.... But really.. the mesage
> generated by the system does not even ressambles to this....
> 



Do you have a "hard deadline" scheduler version of Oberon?
Where did you get it?

> 
>  This mesage does mean: this "toy real-time operation system"
> does not have accomplished a task until  the deadline time
> especified!!! Only this!!!
>