[en] Initial commissionings of the Advanced Photon Source (APS) 7-GeV storage ring and its diagnostics systems have been done. Early studies involved single-bunch measurements for beam transverse size (σ_x ∼ 150 μm, σ_y ∼ 50 μm), current, injection losses, and bunch length. The diagnostics have been used in studies related to the detection of an extra contribution to beam jitter at ∼ 6.5 Hz frequency; observation of bunch lengthening (σ ∼ 30 to 60 ps) with single-bunch current; observation of an induced vertical, head-tail instability; and detection of a small orbit change with insertion device gap position. More recently, operations at 100-mA stored-beam current, the baseline design goal, have been achieved with the support of beam characterizations