As the DOOCS control systems, operating the TESLA Test Facility (TTF) at DESY, is a widely distributed system, for TTF phase 2 approximately 50 front-end- and middle-layer computer with 5 to 10 server processes on each processor are planed. A system with local log files is not sufficient anymore. In addition to the local files a central logging of all error and warnings will be implemented. The architecture consist of a central logging server that receives the log messages in XML format. It is based on a DOOCS server written in C++, using the XML2 library for parsing the XML messages. All message are combined inside a DOM tree. This tree reflects the actual status of all devices in the system. On the client side the server represents a Web Service. Client requests from Java applets or Web browsers are handled via a servlet / Tomcat service. In order to provide a fast online update Java Messaging Service JMS will be used to send single messages to the clients. To allow a logging per device, every message is stored inside a directory tree. On the front-end this error handling is a fully integral part of the DOOCS server library, so no additional programming effort is required. A Java applet will allow the operator to get an overview of the machine status, as well as allowing remote experts to get information of single devices by browsing through a tree like structure closely connected to the TTF nomenclature. First experiences with this implementation will be discussed.
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