Apparatus in a disc drive for transferring data between a rotatable disc and a host computer. An analog pre-processor integrated circuit device incorporates circuitry to carry out analog processing functions including write current driving, readback signal amplification, prewrite compensation, frequency-domain filtering, and equalization. A digital post-processor integrated circuit device incorporates circuitry to carry out digital signal processing functions including Viterbi detection, decoding, error detection and correction, buffering, host interface functions, and data encoding and serialization. The analog pre-processor is preferably mounted within the interior environment of the disc drive to an actuator assembly that supports a head adjacent the disc. The digital post-processor is preferably supported on a printed circuit board mounted to an exterior surface of the disc drive.