MIX file extension - Don Knuth's MMIX emulator file
What is mix file? How to open mix files?
File type specification:
The MIX file extension is also related to MMIX - a machine that operates primarily on 64-bit words. It has 256 general-purpose 64-bit registers that each can hold either fixed-point or floating-point numbers. Most instructions have the 4-byte form `OP X Y Z', where each of OP, X, Y, and Z is a single 8-bit byte.
A *.mix file contains emulator data.