In 1991 there was a very distinct job called system administrator and the really high skilled ones wrote all sorts of system administration tools in awk, Perl, Shell, and sometimes in C. This to me was 'systems programming' for the administration, deployment, automation, and management of the 'systems'.

This was in contrast to "developers" who wrote application code in numerous languages COBOL, Pascal, Fortran, BASIC, etc. And they in general, did not manage the underlying system.

Over the years I think those lines have blurred and the roles are all smashed together sometimes called devops or other terms.