Charged track reconstruction and b-tagging performance in ATLAS

The ATLAS Inner Detector is designed to provide precision tracking informa- tion at LHC luminosities with a hermetic detector covering 5 units in pseudo- rapidity. It features a large silicon tracker subdivided into a pixel and a strip system for precise tracking and primary/secondary vertex reconstruction and to provide excellent b-tagging capabilities. A Transition Radiation Tracker improves the momentum reconstruction and provides electron identification information. The subject of these proceedings is the performance of the ATLAS Inner Detector achieved after its first 2 years of operation. The excellent detector performance and more than a decade of simulation studies provided a good basis for the commissioning of the offline track and vertex reconstruction. Early studies with cosmic events and the ever increasing amount of high quality p-p collision data allowed for rapid progress in understanding of the detector. Today the ATLAS Inner Detector approaches its design values in most relevant performance criteria. High luminosity pileup and tracking in central heavy ion events pose additional challenges. An overview of the recent tracking performance results and the lessons learned during commissioning will be given, including a brief overview of the main b-tagging algorithms and its performances