subprocesses

[James Walter Taylor]

I'm using octave to drive the testing of a pattern recognition
program. An octave script generates a pattern, stores it in a 
file and starts an external process which processes the data.

i.e. a loop around a construct like:

---
V = blah();
fdx=fopen(tmpFile, 'w');
fprintf(fdx, '%d\n', V);
fclose(fdx);

[result,s] = system(['/home/james/newthing <' tmpFile ]); 

---
millions of times.  Well after only a few 10s of thousands of times
I see errors like:

error: unable to start subprocess for `/home/james/newthing </tmp/7241Data.dat'
error: evaluating index expression near line 24, column 14
error: evaluating assignment expression near line 24, column 12
... etc.

And at that point even "ls" produces errors:
---
octave:27> ls
error: couldn't start process for ls!
error: evaluating expression near line 27, column 1
---

Any clues ?

Thanks
James