51.   Of course, Zip and SparQ disks are not compatible with each other.

52.   One flat, circular disk is on one side of the knee, its twin on the other side.

53.   One disk is music.

54.   Physiologically unhealthy disks are stiff and inflexible, increasing back strain and susceptibility to injury.

55.   Since galaxy disks are comparatively small, it is difficult to use their motions as probes of anything but the inmost portions of the surrounding halos.

56.   So hold off if your disk is nearly full.

57.   Some disks are double-sided, with the widescreen version of a film on one side, a TV-tailored format on the other.

58.   Some record company executives want the new DVD audio disks to be playable on CD players as well.

59.   Sony has gone after the computer market, where its single sided disk is compatible with the CD-ROM disks currently used in computers.

60.   System-restore disks are a good idea, in theory.