​Ah - that is the old Research compiler before f77.   I'm not even sure it will compile a full Fortran-IV deck.   As I said, pretty early into USENIX look in the CULC directory and you should find a FTN compiler and the DEC assembler. That was the compiler many of used until the pcc/f77 showed up.

Years later, when DEC released Ultrix, the languages groups formally supported Ultrix.  Besides being more modern versions of the compilers, is they supported the old VMS linker, which was ported to both the 11 and the Vax by Paul Winalski. ​  Not only did he get it run on Unix, he got it work with a.out, and macho files too.  I don't remember if he could grok ELF with it (he would know - maybe I can convince to join this list).   He will carry a lot of DEC history in the middle times, when I was doing startups.