Vapor-compression refrigeration replaced, such as sulfur dioxide. Haloalkanes are also an order(s) of magnitude more expensive than petroleum derived flammable alkanes of similar or better cooling performance. Unfortunately, chlorine- and fluorine-bearing refrigerants reach the upper atmosphere when they escape. In the stratosphere, CFCs break up due to UV radiation, releasing their chlorine free radicals. These chlorine free radicals act as catalysts in the breakdown of ozone through chain reactions. One CFC molecule can cause thousands of ozone molecules to break down. This causes severe damage to the ozone layer that shields the Earth's surface from the Sun's strong UV radiation, and has
S-BASIC for the commercial Spectral UV-Visible software. Jerry Pournelle in 1983 wrote that SBASIC "is quite nice", stating that it "rivals CB-80". He presumed that Kaypro users would "will begin by using Microsoft MBASIC, then start translating their programs into S-BASIC and learn more about structured programming". Pournelle added, "If I had to give an award for the most unreadable computer document I've ever seen, the original S-BASIC manual would win hands down"; however, Kaypro had rewritten it and "is a great deal more sensible". S-BASIC S-BASIC (for Structured Basic) was a "structured" BASIC variant, distributed with Kaypro CP/M systems. It