An Observation Data File (ODF) is a set of files containing data from all XMM instruments obtained during a science observation, stripped of the telemetry headers and wrappers. ODFs are produced by the Observation Data Subsystem (ODS). The data are at that stage uncalibrated, in the format to be read into and processed by the SAS.
Similarly, Slew Data Files (SDFs) contain all data obtained during XMM slews, in the format to be read into and processed by the SAS.
ODFs/SDFs contain science files from each XMM instrument operating during the observation/slew, depending on the mode in which they are operated, and instrument housekeeping information. In addition, ODFs/SDFs also contain spacecraft files (e.g., an attitude history file, reconstructed orbit file etc.) and observation/slew summary files.
A complete description of the files contained in ODFs/SDFs will be presented in the XMM Data Files Handbook (in preparation).