Optical disc drive beam on a smaller spot size and to read smaller pits. DVD lens supports a different focus for CD or DVD media with same laser. With the newer Blu-ray disc drives, the laser only has to penetrate 0.1 mm of material. Thus the optical assembly would normally have to have an even greater focus range. In practice, the Blu-ray optical system is separate from the DVD/CD system. During the times of CD writer drives, they are often marked with three different speed ratings. In these cases, the first speed is for write-once (R) operations, the second speed for re-write (RW)
Capacity to be alone Green saw the fertile interaction of reading/writing as rooted in the capacity to be alone. Capacity to be alone Capacity to be alone is a developmentally acquired ability, considered by object relations theory to be a key to creative living. Julia Kristeva sees it as central to an authentic inner life, as well as to creative sublimations in life and art. D. W. Winnicott in his article of that name (1958/64) highlighted the importance of the capacity to be alone, distinguishing it from both withdrawal and loneliness, and seeing it as derived from an internalisation of the non-intrusive background presence