To invalidate index buffers, you could perform the following steps:

1. In the ACB, specify:
   • STRNO>1.
   • MACRF=NSR to indicate nonshared resources.
   • Let the value for BUFNI default to the minimum.
2. Ensure that your index is a multilevel index.
3. Ensure that all requests are for positioning by specifying the following:
   • GET RPL OPTCD=DIR
   • POINT
   • PUT RPL OPTCD=NUP