NEC announced the NEAC System 100 in August 1973 and began shipping the system in October of that year. In an era when operating systems did not yet exist, this system made use of a program loader, which read programs into its main memory from the primary external storage unit, usually using magnetic cassette tape media. The system ran BEST (Beginner's Efficient & Simple Translator) as its application development program. BEST had been newly developed for office computers and was a basic programming language similar to COBOL that could be learned quickly. BEST could be used to create various office programs, such as billing programs, inquiries (i.e., updates), and online form processes (i.e., adding functions at a later time).
The first NEC software for office computers included compilers for developing application programs and various utilities for manipulating programs and data.
The primary office computer software included:
- Compiler for BEST (a basic programming language)
- Source update (for source programs): equivalent to a modern text editor
- Object update: utility for managing executable programs
- Sort utility
- File utility (for copying, printing, etc.)
With the rising need for COBOL, a programming language for business and office applications, to create sophisticated business processing programs, NEC shipped NEAC System 100 COBOL in February 1974. The use of this COBOL version really took off starting with the high-end NEAC System 100G and 100H office computers, which succeeded System 100 and began shipping in August 1975, because they were equipped with file storage units sufficient for COBOL programming.