Engineer Dmitry Grinberg ran Linux with a Debian rootfs environment on a CPU released through 1971 year. It is the Intel 4004 model, which includes 2,300 transistors and 4 kilobytes of permanent memory. The chip took 8 days just to boot the operating system.
The difficulty with the idea was that the Intel 4004 did not support any of the existing compilers for the C language. These allow you to translate text written in a programming language into machine code.
To solve the problem, Greenberg created an assembler emulator that allowed the Intel 4004 to run an environment based on the Linux kernel. However, the low performance of the processor is obvious - processing one virtual second in the emulated software requires up to four hours of calculations on the real system.
For example, it takes 30 days to render the Mandelbrot set at 13x40 resolution. The system itself runs on the processor for eight days. To give you an idea of how slow this is, in the video below, one second of timing corresponds to two minutes of real time. Look.