Dual read-record head for magnetic card machine actuator

Dual speed tape drive system for an endless loop dictating...

Dual stack optical data storage medium

Dual stack optical data storage medium and use of such medium

Dual transducer assembly with linear adjustment

Dual wavelength optical system

Dual-function information-carrying sheet device

Dual-layer dvd disc and method and apparatus for making same

Dual-layer magnetic recording tape

Dual-layer quadruplex video recording tape

Dual-stack optical data storage medium for write once recording

Duplicating apparatus for making magnetic records

Dust cover

Dust door incorporating tape reel lock

Dust remover for phonographs

Dvd disc with four information layers, and method for making...

Dvd random shuffle method

Dvd replication of encoded content

Dvd-authoring system and method

Dvd-authoring system and method