Abstract: Systems, methods, and computer program products for improving the performance of computer-implemented I/O operations for complex applications, such as databases. Applications that are ported to the IBM OS/390 UNIX System Services may be enhanced by the present invention to improve I/O performance. That is, the present invention may be implemented by augmenting general-purpose I/O access features with specialized I/O access operations that are tailored to enhance I/O access performance for complex applications, such as databasbes, on the IBM OS/390 UNIX System Services.