We use a theorem by Buskes-Kusraev on the automatic symmetry of an order bounded orthosymmetric bilinear map to give a complete description of order bounded derivations on a pseudo f -algebra. This generalizes a well known theorem by Colville, Davis, and Keimel. Then, we investigate the commutator [, ] of an orthosymmetric bilinear map using an order theoretical approach. This leads to a generalization of the Buskes-Kusraev result to a larger class of orthosymmetric bilinear maps.