  We report on the operation and performance of the ATLAS Semi-Conductor
Tracker (SCT), which has been functioning for 3 years in the high luminosity,
high radiation environment of the Large Hadron Collider at CERN. We also report
on the few improvements of the SCT foreseen for the high energy run of the LHC.
We find $99.3\%$ of the SCT modules are operational, the noise occupancy and
hit efficiency exceed the design specifications; the alignment is very close to
the ideal to allow on-line track reconstruction and invariant mass
determination. We will report on the operation and performance of the detector
including an overview of the issues encountered. We observe a significant
increase in leakage currents from bulk damage due to non-ionizing radiation and
make comparisons with the predictions.
