ontape within a script

Apologies first of all; I've seen this question posted before, but I can't find the answer in any archives. When running an ontape -s, if the tape is not ready, the message to prepare the tape will be repeated. Within a script, this will simply start a tight loop which will quickly fill up the script logfile's file system. I've seen a technique described which limits the number of re-tries to a finite number, say 10 or 100. Can anyone remind me how to do this? Thanks Neil Truby Chase Manhattan Bank Bournemouth, UK neil.truby@chase.com