データゼネラル
Concentric Data Systems, Inc. was founded in December 1979 by John J. Henderson and Jonathan Sachs, both having left their jobs as system programmers at Data General Corporation. Originally, the company undertook a variety of software consulting projects for the Data General line of computers. In 1981, the company developed a spreadsheet product, CompuCalc, that ran on Data General hardware and was modeled after VisiCalc.