- Butterflies are winged insects from the lepidopteran suborder Rhopalocera, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The group comprises the superfamilies Hedyloidea (moth-butterflies in the Americas) and Papilionoidea (all others). The oldest butterfly fossils have been dated to the Paleocene, about 56 million years ago, though they likely originated in the Late Cretaceous, about 101 million years ago.
- IBM PC DOS 1.00 (pcjs.com)
PC DOS 1.00 was completed in August 1981 and announced at an IBM press conference on August 12, 1981, when IBM introduced the original IBM PC (Model 5150). It was released on one single-sided (160Kb) diskette, and included 23 BASIC Programs.