Frederick C. Ihrer, 80, a software developer who designed one of the first “point of sale” systems used in restaurants, died Nov. 10 at Frederick Memorial Hospital.

He had kidney ailments and congestive heart failure, his daughter Sharon River Hansen said.

Mr. Ihrer, an early software developer for the Pentagon, started a software company, Comress, based in Rockville, in 1962. After his company merged with another in 1972, Mr. Ihrer bought the Comus Inn, a historic country inn and restaurant in northern Montgomery County. He sold it in 1989.

In the 1970s, he developed a system of software for use by restaurant workers, now widely known as “point of sale,” or POS. In 1980, Mr. Ihrer founded Comus Restaurant Systems, a business that developed and marketed software for restaurants. He operated the company until his death.

In the 1970s, he also developed the Sheraton-Potomac Inn in Rockville. He later sold the property.

Frederick Charles Ihrer III was born in Burlington, Iowa, and grew up in Denver. He attended Regis University in Denver.

After coming to Washington in 1957, Mr. Ihrer worked at the Pentagon and, later, for RCA before starting his company. He was a Frederick resident.

His wife of 52 years, Joanne McCarthy Ihrer, died in 2002.

Survivors include six children, Stone Wolfsong of Kona, Hawaii, Ronald J. Ihrer of New Bern, N.C., Sharon River Hansen of Colorado Springs, Kippi Waters of Port Townsend, Wash., and Sheila Froedge and Pia Lily, both of Bowling Green, Ky.; 13 grandchildren; and 10 great-grandchildren.

— Matt Schudel