This redbook covers problem determination and troubleshooting on the RS/6000 platform. It is intended as a guide to the approach that should be adopted when attempting to resolve a problem on an RS/6000 system running AIX Version 4.3. It is not intended to replace the comprehensive documentation available for the AIX operating system or the System Installation and Service Guides available for RS/6000 system hardware. Instead, it should be considered as a useful supplement to guide you through the problem determination process. A problem can manifest itself in many ways, and very often the root cause of the problem is not obvious. This redbook describes an approach to problem determination that will guide you through the initial steps in problem diagnosis and to narrow down and identify the component or subsystem that is experiencing a problem. In addition to helping you determine the likely cause of your problem, this redbook describes some of the most common problems that can occur with AIX systems and, where possible, describes the actions you can take to resolve them. This redbook is a valuable tool for system administrators and other technical support personnel who deal with RS/6000 and AIX problems. The information in this redbook is not intended to completely cover problem determination on RS/6000 SP systems or RS/6000 systems configured as nodes in an HACMP cluster.