Chapter 2. DiagnosticsThis chapter describes the diagnostic tools that are available to help you solveproblems that might occur in the server.If you cannot locate and correct the problem using the information in this chapter,see Appendix A, “Getting help and technical assistance,” on page 167 orhttp://www.ibm.com/servers/eserver/support/xseries/index.html for more information.Diagnostic toolsThe following tools are available to help you diagnose and solve hardware-relatedproblems:v POST beep codes, error messages, and error logsThe power-on self-test (POST) generates beep codes and messages to indicatesuccessful test completion or the detection of a problem. See “POST” for moreinformation.v Troubleshooting tablesThese tables list problem symptoms and actions to correct the problems. See“Troubleshooting tables” on page 37.v Light path diagnosticsUse the light path diagnostics to diagnose system errors quickly. See “Light pathdiagnostics” on page 50 for more information.v Diagnostic programs, messages, and error messagesThe diagnostic programs are the primary method of testing the majorcomponents of the server. The diagnostic programs are in read-only memory onthe server. See “Diagnostic programs, messages, and error codes” on page 60for more information.v Real Time DiagnosticsReal Time Diagnostics can help you diagnose problems in certain devices whilethe operating system is running, to prevent or minimize server downtime. See“Real Time Diagnostics” on page 78 for more information.POSTWhen you turn on the server, it performs a series of tests to check the operation ofthe server components and some optional devices in the server. This series of testsis called the power-on self-test, or POST.If a power-on password is set, you must type the password and press Enter, whenprompted, for POST to run.If POST is completed without detecting any problems, a single beep sounds, andthe server startup is completed.If POST detects a problem, more than one beep might sound, or an error messageis displayed. See “Beep code descriptions” on page 14 and “POST error codes” onpage 20 for more information.© Copyright IBM Corp. 2007 13
