Hi Peter,

>>Double check that you're indeed using unbuffered IO everywhere. I am using sysseek, syswrite, sysread.
>>If I understand you correctly, you're forking
>>children to read:

Yes. Each child write its current status to a file that looks like a table.

>>use strace -f instead for the _real_, _complete_
>>trace.

The above strace output was generated with -f for each child.


>>consider to explicitly open the files separately in
>>each child (my bet - issues both for the pointer
>>AND for the locking).

Hmmm, okay, that could be the solution. The parent is forking and the children uses all opened handles of the parent.

I test it! Thanks a lot for the suggestions!

Cheeers,
Jonny Update: removed small tags