A fluidics handling system for transferring a fluid from a fluid-source reservoir to a fluid-target reservoir comprising: at least one dispensing head; a holder support; a removable holder for holding at least one of a removable fluid-source reservoir and a removable fluid target reservoir, the removable holder comprising an apparatus for precisely and repeatably positioning the removable holder on the holder-support; and a motion stage for moving the holder support, wherein the holder-support comprises: a first datum for engaging the removable holder and for restricting movement of the removable holder along an x-axis and a mutually orthogonal y-axis, and defining a first point in a z-axis, the z-axis mutually orthogonal to the x-axis and the y-axis; a second datum for engaging the removable holder and for at least partially locating the removable holder along at least one of the x-axis and the y-axis and defining a second point in the z-axis; and a third datum for engaging the removable holder and defining a third point in the z-axis, and wherein the apparatus for repeatably positioning the removable holder on the holder-support further comprises: a first element for mating with the first datum, and for restricting movement of the removable holder along the x-axis and the mutually orthogonal y-axis; a second element for mating with the second datum, and for at least partially locating the removable holder along at least one of the x-axis and the y-axis; and a third element for mating with the third datum. at least one dispensing head; a holder support; a removable holder for holding at least one of a removable fluid-source reservoir and a removable fluid target reservoir, the removable holder comprising an apparatus for precisely and repeatably positioning the removable holder on the holder-support; and a motion stage for moving the holder support, wherein the holder-support comprises: a first datum for engaging the removable holder and for restricting movement of the removable holder along an x-axis and a mutually orthogonal y-axis, and defining a first point in a z-axis, the z-axis mutually orthogonal to the x-axis and the y-axis; a second datum for engaging the removable holder and for at least partially locating the removable holder along at least one of the x-axis and the y-axis and defining a second point in the z-axis; and a third datum for engaging the removable holder and defining a third point in the z-axis, and wherein the apparatus for repeatably positioning the removable holder on the holder-support further comprises: a first element for mating with the first datum, and for restricting movement of the removable holder along the x-axis and the mutually orthogonal y-axis; a second element for mating with the second datum, and for at least partially locating the removable holder along at least one of the x-axis and the y-axis; and a third element for mating with the third datum. a first datum for engaging the removable holder and for restricting movement of the removable holder along an x-axis and a mutually orthogonal y-axis, and defining a first point in a z-axis, the z-axis mutually orthogonal to the x-axis and the y-axis; a second datum for engaging the removable holder and for at least partially locating the removable holder along at least one of the x-axis and the y-axis and defining a second point in the z-axis; and a third datum for engaging the removable holder and defining a third point in the z-axis, and wherein the apparatus for repeatably positioning the removable holder on the holder-support further comprises: a first element for mating with the first datum, and for restricting movement of the removable holder along the x-axis and the mutually orthogonal y-axis; a second element for mating with the second datum, and for at least partially locating the removable holder along at least one of the x-axis and the y-axis; and a third element for mating with the third datum. a first element for mating with the first datum, and for restricting movement of the removable holder along the x-axis and the mutually orthogonal y-axis; a second element for mating with the second datum, and for at least partially locating the removable holder along at least one of the x-axis and the y-axis; and a third element for mating with the third datum.