100 positions the heads 112 adjacent the landing zones 118 this serves to place the actuator 110 in a parked position while data transfer operations are suspended during a period of inactivity preferably the apparatus 120 is formed using a suitable injection molding operation from a durable polymer such as a polycarbonate resin but may be formed from other moldable rigid polymers or materials such as engineered ceramics fig2 also shows the outer filter retention member 140 provides an outer filter retention channel 152 and the inner filter retention member 142 provides an inner filter retention channel 154 wherein fluidic currents developed by rotation of the disc 108 of fig1 of the dsd 100 are substantially sealed from migration around the secondary filter 128 of fig1 and passed through the secondary filter 128 fig3 shows a disc stack assembly 156 formed from a number of discs 108 stacked on the spindle motor 106 and clamped thereto by a disc clamp 158 the disc stack assembly 156 and the actuator 110 in combination collectively form mechanically active components mac 160 of the dsd 100 during data exchange operations of the dsd 100 the mac 160 generates sub micron particles and dislodges sub micron particles from other components internal to the dsd.