Reminds me of a resource serialization problem I had back in the old uni days, where I had to synchronize data between parent/children.

One of the solutions was to use an external database, where database I/O's were handled by an independent (external) process.

Another solution was to use shared memory (I was coding it in C then). I think it must be our liz who has posted this module on CPAN (well done liz) - forks::shared. It states that:

The "forks::shared" pragma allows a developer to use shared variables with threads (implemented with the "forks" pragma) without having to have a threaded perl, or to even run 5.8.0 or higher.

And example pulled from CPAN -

  use forks;
  use forks::shared;

  my $variable : shared;
  my @array    : shared;
  my %hash     : shared;

  share( $variable );
  share( @array );
  share( %hash );

  lock( $variable );
  cond_wait( $variable );
  cond_signal( $variable );
  cond_broadcast( $variable );
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Take a look at this module, I think this might be a more elegant solution to your problem.