1. The protective plastic bag that accompanies 3.5-inch microfloppy diskettes. Rarely, also used of (paper) disk envelopes. Unlike the write protect tab, the condom (when left on) not only impedes the practice of SEX but has also been shown to have a high failure rate as drive mechanisms attempt to access the disk - and can even fatally frustrate insertion.
2. The protective cladding on a light pipe.