Sounds like unix to me.
Indeed, it sounds like the author is looking for the UNIX of the 21st century: * Widely reusable meaning: everything behaves like a file. The types of files we can have are defined by specs: an Image can be described as a PNG file, which every process can understand. A table can be a CSV or a SQLite file. A Conversation can be a maildir folder. We might not have the best descriptions of "things" but we do have someth…
Under Plan 9, UNIX's everything is a file metaphor is extended via a pervasive network-centric filesystem, and the cursor-addressed, terminal-based I/O at the heart of UNIX-like operating systems is replaced by a windowing system and graphical user interface without cursor addressing, although rc, the Plan 9 shell, is text-based.
Source: https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs
Many of the ideas from Plan 9 were implemented as user space programs on a variety of Unix-like operating systems:
Plan 9 from User Space provides many of the ideas, applications, and services from Plan 9 on Unix-like systems. It runs on FreeBSD (x86, x86-64), Linux (x86, x86-64, PowerPC and ARM), Mac OS X (x86, x86-64, and PowerPC), NetBSD (x86 and PowerPC), OpenBSD (x86 and PowerPC), Dragonfly BSD (x86-64), and SunOS (x86-64 and Sparc).
Source: https://9fans.github.io/plan9port/man/man1/intro.html