FPGA Modernizes DEC J-11 with the Resurrection of UNIX Version 1

In the world of computer science, the PDP-11 stands as a significant milestone in the development of UNIX and the C programming language. First introduced in the 1970s, the PDP-11 was initially expensive and was primarily found in research labs and industries. However, [ryomuk], a tech enthusiast, has brought this historical computer system back to life with a modern twist.

In 2022, [ryomuk] embarked on a project to emulate a PDP-11 system using a Tang Nano 20k FPGA and an original DEC J-11. The goal was to enable the machine to run the first version of UNIX. To achieve this, [ryomuk] designed a PCB for the DEC microprocessor and the FPGA to be mounted together.

The FPGA in this setup emulates the memory system, UART, and instruction set of a PDP-11 system. Moreover, the PCB design allows for the emulation of disk drives and co-processors, essential components for running UNIX. Interestingly, the original DEC chip in the setup is left to its own devices, working alongside the FPGA to recreate the authentic PDP-11 experience.

The PDP-11 paper tape emulator built by [ryomuk] also runs a version of BASIC from the era, adding another layer of historical accuracy to the project. The completed system, compact enough to fit into an ATX case, makes this piece of computer history more accessible than ever.

[RetepV] provided a tip regarding this build, further fuelling [ryomuk]'s passion for the project. The PCB includes all necessary jumpers and wiring for the PDP-11 computer to run UNIX, ensuring a smooth emulation experience.

[ryomuk]'s build is a modern version of a PDP-11 computer, offering an interesting representation of the early days of computer science. By combining an FPGA with an original DEC J-11, [ryomuk] has crafted a unique blend of old and new, keeping the spirit of innovation alive in the realm of computer science. This build serves as a testament to the enduring fascination with the history of computing and the relentless pursuit of knowledge in this ever-evolving field.