Performance of ALICE detector and electronics under first beam conditions

ALICE (A Large Ion Collider Experiment) is a general purpose heavy-ion detector at the CERN LHC addressing the physics of strongly interacting matter and the quark-gluon plasma in nucleus-nucleus collisions. ALICE has been recording physics data since the first proton-proton collisions at LHC as reference for the heavy-ion programme and to address physics topics for which it is complementary to the other LHC detectors. This paper aims to provide a concise description of the ALICE experiment, with entire emphasis on instrumentation and electronics related topics, as it has been operating since the beginning of the LHC 7 TeV p-p collisions programme (March 2010) up to date. The performance, stability and reliability of selected detectors and central systems are discussed. A description of the typical proton-proton data taking experience is given. Selected topics related to timing and synchronization of systems, luminosity measurements and SEU effects are finally presented.