Flash memory and methods of fabricating the same are disclosed. Y, A, and B are as described herein. The head is provided with at least one radially extending slot receiving a plate of the reamer. Further, the second valve can continue providing capacity control, should the pulse width modulation suction valve fail. The apparatus of this invention also permit a compound library to be rapidly screened to determine if any member of the library has an affinity for the target receptor as measured by a pre-selected indicator compound.