|The operating system designed specially for the VAX family
was based on the conception of 4 GB's of virtual memory, a four levels
of processor mode (Kernel, Executive, Supervisor, User), and one
of the most significant PDP-11 operating system: RSX-11 (the utilities
came mostly from the latter; whe first version of VMS to feature only native
code was 3.0).
The development of the first version (V1), codenamed "Starlet" started in 1975, led by Roger Gourd, assisted by Dave Cutler, Dick Husvedt and Peter Lipman. The first machine that the code ran on was a PDP-11 with modified microcode, called the "VAX Hardware Simulator", then they changed to the first VAX-11/780 prototype. One of the main feature of the OS/hardware was the ability to run PDP-11 code, the next goal was to maintain compatibility with newer OS releases and hardware models: the newest release of VMS still runs on the oldest hardware...
Main features of V1: 64 MB maximal physical memory, multi-user multitasking, DCL (Digital Command Language) shell, DECnet-support, FORTRAN IV compiler. The first VAX11/780-VMS configuration was shipped in 1978, the customer was the Carniege-Mellon University.
VT100: Digital's new CRT video terminal complied with ANSI regulations, and immediately became a de-facto standard. Main featrues: 24x80 or 14x132 characters, keyboard with 83 keys, support for special escape characters. It is interesting to note, that the vt100 features found in the termcap library of UNIX systems is based on the VT102, which was an enhanced version of the terminal.
DECsystem-2020: Digital's last 36-bit computer, a small-sized mainframe.