Correction fluid the Montreal Protocol on Substances That Deplete the Ozone Layer, and then the slightly safer trichloroethylene. Thinners currently used with correction fluid include bromopropane. Because it contains organic solvents (volatile organic compounds), unused correction fluid thickens over time as volatile solvents escape into the air. It can become too thick to use, and sometimes completely solidifies. Therefore, some manufacturers also sell bottles of solvent as "thinner", a few drops of which will return the correction fluid to its original liquid state. To avoid the inconveniences of organic solvents (safety and availability), some brands of fluid are water-based. However, those have
Separation of concerns 1989, Chris Reade wrote a book titled "Elements of Functional Programming" that describes separation of concerns: Reade continues to say, Separation of concerns is crucial to the design of the Internet. In the Internet Protocol Suite, great efforts have been made to separate concerns into well-defined layers. This allows protocol designers to focus on the concerns in one layer, and ignore the other layers. The Application Layer protocol SMTP, for example, is concerned about all the details of conducting an email session over a reliable transport service (usually TCP), but not in the least concerned about how the transport service