Ed Yourdon, founder of Yourdon, Inc.

Image: Ed Yourdon

Ed Yourdon, founder of Yourdon, Inc.

Yourdon was a pioneer of the software engineering methodology and a proponent of structured analysis. He is also known as a co-developer of object-oriented analysis/design.

Image: Ed Yourdon

Gary Kildall, founder of Digital Research

Image: Stewart Cheifet/the Computer Chronicles

Gary Kildall, founder of Digital Research

Kildall is known as the creator of the CP/M operating system. IBM made an unsuccessful attempt at licensing CP/M for the IBM PC.

Image: Stewart Cheifet/the Computer Chronicles

VisiCalc founders Daniel Bricklin and Robert Frankston

Image: VisiCorp

VisiCalc founders Daniel Bricklin and Robert Frankston

VisiCalc is often regarded as the first spreadsheet program, originally released for the Apple II. VisiCalc was a big part of the personal computer becoming a business tool.

Image: VisiCorp

Oracle founders Larry Ellison (pictured), Bob Miner, and Ed Oates

Image: James Martin/CNET

Oracle founders Larry Ellison (pictured), Bob Miner, and Ed Oates

Ellison, Miner, and Oates founded Software Development Laboratories in 1977, which later became Oracle. Today, the company is known as a leader in ERP and CRM software.

Image: James Martin/CNET

SAP founders in 1988: Klaus Tschira, Hans-Werner Hector, Dietmar Hopp, Hasso Plattner (from left to right)

Image: SAP AG

SAP founders in 1988: Klaus Tschira, Hans-Werner Hector, Dietmar Hopp, Hasso Plattner (from left to right)

SAP was founded as a private partnership in June of 1972. The company began by creating enterprise software for payroll and accounting.

Image: SAP AG

Anthony James Barr, developer of the SAS language

Image: Julian Horwich

Anthony James Barr, developer of the SAS language

Barr founded the Statistical Analysis System in the late 1960s. The SAS Institute was incorporated by Barr and Jim Goodnight in the 1970S.

Image: Julian Horwich

Apple II DOS creator Paul Laughton

Image: Paul Laughton

Apple II DOS creator Paul Laughton

In 1978, Laughton was working for Shepardson Microsystems and was contracted to build Apple’s first DOS for the Apple II.

Image: Paul Laughton

Richard Lawson of Lawson Software

Image: Purdue University

Richard Lawson of Lawson Software

Richard Lawson founded Lawson Software in 1975 with his brother Bill and John Cerullo. The company began providing custom mainframe software for IBM and went public in 2001.

Image: Purdue University

Xerox PARC lab team

Image: PARC/Xerox

Xerox PARC lab team

Bob Taylor and the PARC team are responsible for tech innovations such as graphical user interface (GUI) and Ethernet.

Image: PARC/Xerox