About this strange computer, IBM said that it was "A unique combination of features and a new dimension in small computers".
The 9000 (its reference name) was first presented in June 1982 at the COMDEX show in Atlantic City. The system ans peripherals was manufactured by IBM's instrumentation division in Danbury, Connecticut.
It was first and foremost intended to be used by scientists and engineers for instruments control and data acquisition. Its modular concept made the system to grow easily and allowed the user to adapt it to each particular environment.
The mainframe was equipped with five I/O interfaces allowing it to be connected to a variety of laboratory instruments. Three user-input devices was available: Two programmable sensitive keyboards and a standard PC-type keyboard. A high-resolution display could be supplemented by a 4-color plotter-printer.
The 9000 has been engineered with crowded lab benches in mind: The modules stack vertically to conserve space.
The unit used a specific real time and multitasking operating system custom designed by IBM, as well as standard programming languages: BASIC, PASCAL, FORTRAN. It also ran Xenix, which was a form of UNIX written for Motorola 68000 computers by Microsoft.
Note that the history of Xenix is quite a bit more nuanced than "Xenix, which was a form of UNIX written for Motorola 68000 computers by Microsoft". See https://en.wikipedia.org/wiki/Xenix for the full Xenix story.