The lecture aims to establish a foundational understanding of how a computer works by focusing on three core ideas:

1. The Computer's Blueprint (The Von Neumann Model)
2. The Computer's Language (The ISA)
3. The Computer's Process (The Instruction Cycle)

1. The Computer's Blueprint: The Von Neumann Model

Von Neumann Model is the standard organizational structure for most computers. There are five components in the Von Neumann Model which are:

1. Input

2. Output

3. Logic Unit

   This is where computations happen. It contains the Arithmetic and Logic Unit (ALU), which performs operations like addition, subtraction, and logical AND/NOT. It also contains a small number of very fast storage locations called registers for holding data that is being actively used.

4. Memory

   This is a large pool of storage that holds both the program (the list of instructions) and the data the program needs. A key principle of this model is that instructions and data are stored together in the same memory space. Memory is much larger but also much slower to access than the processor's registers.

5. Control Unit

   This is the director of the entire system. It fetches instructions from memory, interprets what they mean, and sends out signals to coordinate the actions of the Processing Unit and Memory. It uses a special register called the Program Counter (PC) to keep track of the memory address of the next instruction to be executed.

Key Takeaway: The Von Neumann model's core properties are that

1. it stores the program and data in the same memory and
2. it processes instructions sequentially, one after another, as tracked by the Program Counter.

2. The Instruction Set Architecture (ISA)

The ISA is the contract between software and hardware. It defines every operation the processor can physically perform.