The document describes the basic organization of a microcomputer system and Von Neumann architecture. It explains that a microcomputer consists of a CPU, memory, input/output and that the CPU contains an ALU, control unit and register file. It describes the fetch-decode-execute cycle where the CPU fetches instructions from memory and executes them. It also discusses machine code, assembly language and different levels of programming languages from machine code to high-level languages. Finally, it provides the rationale for using low-level languages like assembly to understand computer hardware and develop certain system software.