OSM(4,F) AIX Technical Reference OSM(4,F) ------------------------------------------------------------------------------- osm PURPOSE Provides the interface to AIX messages. DESCRIPTION The osm driver collects system messages provided by the AIX kernel and application programs. It is found in all AIX systems. These system messages are available to a daemon reading this file. System messages have two sources: o The AIX kernel provides messages by calls to the kernel printf routine. o Application programs open and write to this file. Operating system messages are stored in a circular buffer in the system and can be read or written using the osm* special files. A read from osm* files returns some portion of the data in the circular buffer. A write to the files adds user data to the current end of the circular buffer. Any number of users may use osm* files in the same instance of time. Read operations from the osm file start at the current end of the circular buffer and wait for new data to be added. Read operations from the file /dev/osm.curr start at the beginning of the circular buffer and return 0 bytes when the current end of the buffer is reached. Read operations from the /dev/osm.all file start at the beginning of the circular buffer, go to the current end of the circular buffer, and wait for new data to be added. Note: When using the crash subcommand osm to display these system messages, you will occasionally find messages that could be cause for concern had they been displayed on the console. However, since the kernel and application programs open and write to this file, these messages can be normal. For example, /etc/inittab contains "kill -9 -1" in the stanza for level 2. So /etc/osm would receive the message "WARNING: 'PID' has killed all processes" whenever the system went to multi-user status. FILE /dev/osm* RELATED INFORMATION In this book: "rasconf." In the Commands Reference: "crash." Processed June 6, 1991 OSM(4,F) 1