Heteroatom (sulfur, nitrogen and oxygen) removal from liquids-derived from coal

A relational database is a time varying collection of relations; a relational algebra system is a programming system which allows a user to create and modify relational databases. Here is described a purely interactive relational algebra system designed for use in the microcomputer environment.

This microcomputer relational algebra system, named MICRAs, is written entirely in the PASCAL language and resides in the environment of the UCSD PASCAL system designed for mini and micro computers. MICRAS keeps created databases on floppy disk but automatically makes core resident that part of any subject database the user is working with. MICRAs provides a wide range of commands allowing not only standard database manipulation but also direct user control over the operating system like maintenance features.

It is believed that MICRAs and its descendants will prove to be useful and interesting to microcomputer users exploring the relational approach to databasing and its limitations.