Charged particle yields and spectra in p+p and heavy ion collisions with ATLAS at the LHC

The ATLAS experiment has extensive charged particle tracking over full azimuth and within |η|<2.5. The performance of this system is illustrated and some of the first results for pp collisions are presented. The prospects for tracking in the expected high-multiplicity heavy ion environment are shortly commented. The tracking performance within jets, which is essential for the measurement of jet fragmentation functions, will also be shortly presented.