Either HFS or HFS + is supported in Pro Tools 5.0 and up. However, for compatibility with older versions of Pro Tools (prior to 5.0), drives should be formatted as HFS (Mac OS standard). Due to the greater number of allocation blocks with HFS+, you will experience longer "prime times" when recording. In other words, you will experience a delay between the time you initiate recording and the time recording actually gets underway. Other than that, there is no perceivable difference in performance between HFS+ and HFS. There is a preference in Pro Tools 5.x that allows the user to specify the length of record time. By limiting the allocated hard drive space the "prime time" can also be shortened.To limit the space for recording:1. Choose Setups > Preferences and click Operation.2. Under the Open Ended Record Allocation option, select Limit To and enter a number of minutes to be allocated. The number of minutes specified is allocated for each record-enabled track. You may find it necessary to experiment with this number to achieve the desired performance and recording.