protected function executeRaw($command)
    {
        $pipes = null;
        $this->process = proc_open($command, $this->descriptorspec, $pipes);
        if (!is_resource($this->process)) {
            throw new Exception_SystemProcessIO('Failed to execute');
        }
        $this->debug('Execute successful');
        $this->debugStatus();

        $this->pipes['in'] = &$pipes[0];
        $this->pipes['out'] = &$pipes[1];
        $this->pipes['err'] = &$pipes[2];

        return $pipes;  // in case you need more streams redirected
    }