In the early 1980s, the so-called "DECUS tapes" were a worldwide system for transmission of free software for users of DEC equipment. Operating systems were usually proprietary software, but many tools like the "TECO" editor, "Runoff" text formatter, or "List" file listing utility, etc. were developed to make users' lives easier, and distributed on the DECUS tapes. These utility packages benefited DEC, which sometimes incorporated them into new releases of their proprietary operating system. Even compilers could be distributed and for example Ratfor (and Ratfiv) helped researchers to move from Fortran coding to structured programming (suppressing the GO TO statement). The 1981 Decus tape was probably the most innovative by bringing the Lawrence Berkeley Laboratory "Software Tools Virtual Operating System" which permitted users to use a Unix-like system on DEC 16-bit PDP-11s and 32-bit VAXes running under the VMS operating system. It was similar to the current cygwin system for Windows. Binaries and libraries were often distributed, but users usually preferred to compile from source code.