[TUHS] Will someone please explain the history and usage of gpasswd / newgrp / sg?

Hi, Will someone please explain the history and usage of gpasswd / newgrp / sg? I've run across them again recently while reading old Unix texts. I've been aware of them for years, but I've never actually used them for anything beyond kicking the tires. So I figured that I'd inquire of the hive mind that is TUHS / COFF. When was the concept of group passwords introduced? What was the problem that group passwords were the solution for? How common was the use of group passwords? I ran into one comment indicating that they used newgrp to work around a limitation in the number of (secondary) groups in relation to an NFS implementation. Specifically that the implementation of NFS they were using didn't support more than 16 groups. So they would switch their primary group to work around this limit. Does anyone have any interesting stories related to group passwords / gpasswd / newgrp / sg? -- Grant. . . . unix || die