Before software repositories like CPAN, NPM, or PyPI, developers used user groups like DECUS and SHARE to share code via catalogs in the 1950s and 1960s. These groups promoted discoverability of software and maintained quality standards. Shared code focused on reusable subroutines rather than standalone programs. Initial concerns were about accuracy, efficiency, and documentation, with a review process involving multiple individuals. By the 1970s, user groups saw a shift towards sharing full programs. DECUS became the largest user group in 1961. Languages like FORTRAN, assembly, and PAL were commonly used. The focus on technical work and education led to the majority of programs being in FORTRAN.
https://ztoz.blog/posts/user-group-reuse/