Structures, subassemblies, devices, systems, and subsystems selected from: (1) a unitary holographic drive head assembly mounting structure; (2) an assembly including a unitary holographic drive head assembly mounting structure and a plurality of holographic drive head components and/or subassemblies; (3) a subassembly including a spatial light modulator, detector array, and a beam splitter; (4) a device including a spatial light modulator and a physical aperture positioned over or an imaged aperture projected onto the photoactive area of the spatial light modulator; (5) a system for optically aligning or pointing a laser in a holographic drive head assembly; (6) a light source subassembly including a laser, a fiber coupling lens; and an optical fiber having a fiber connector ready output end; and (7) a light source subsystem including a laser source, beam conditioning optics, fiber coupling optics for receiving the conditioned light beam, and a fiber optic connector for receiving the conditioned light beam from the fiber coupling optics.