✨ Introduction:

Before computers could store programs, they were programmed by manually rewiring circuits.
In 1945, John von Neumann proposed a revolutionary idea:

👉 Store programs inside the computer memory — just like data!

✅ This made computers faster, easier to program, and more flexible.

🔥 What is the Stored Program Concept?

The Stored Program Concept means:
- Both data and instructions (programs) are stored in the same memory.
- CPU fetches instructions and data from memory and executes them.

🧠 Key Features of Stored Program Concept:

Feature	Explanation
Same Memory	Data and Program stored together
Sequential Execution	Instructions are fetched one after another
Flexibility	Easy to change program by changing memory
Speed	No need for manual reprogramming

🛠️ Von Neumann Architecture

Proposed by John von Neumann in 1945.
It is a model showing how a computer should be organized based on the Stored Program Concept.

📑 Components of Von Neumann Architecture:

Component	Description
Memory	Stores data and program instructions
Control Unit (CU)	Fetches and decodes instructions
Arithmetic Logic Unit (ALU)	Performs calculations and logical operations
Input Unit	Sends data from outside world into the computer
Output Unit	Sends results from computer to outside world
Registers	Small memory units inside CPU for quick access

🖋️ Diagram of Von Neumann Architecture:

          +------------------+
          |      Memory       |
          | (Program + Data)  |
          +--------+---------+
                   |
        +----------v-----------+
        |        CPU            |
        | +------+   +---------+ |
        | |  CU  |   |   ALU   | |
        | +------+   +---------+ |
        +----------+------------+
                   |
         +---------v--------+
         |  Input / Output   |
         +------------------+

⚙️ How Von Neumann Architecture Works (Simple Steps):

Fetch:
The Control Unit fetches the instruction from memory.
Decode:
The Control Unit decodes the instruction (understands what needs to be done).
Execute:
ALU performs the necessary calculations or operations.
Store/Output:
Results are stored back in memory or sent to the output unit.

➡️ Then the next instruction is fetched, and the cycle repeats.

🎯 Key Characteristics of Von Neumann Architecture:

Characteristic	Meaning
Stored Program	Programs and Data together in memory
Sequential Execution	One instruction at a time
Single Memory Bus	Same bus for instruction and data transfer (causes Von Neumann Bottleneck)
Simplified Design	Easier to build and manage computers

🚨 Von Neumann Bottleneck

Since data and instructions share the same bus, only one transfer at a time can happen.
This slows down the system.
Known as the Von Neumann Bottleneck.

📚 Real Life Examples of Von Neumann Architecture:

Most personal computers (PCs).
Laptops, smartphones, and tablets.
Early computers like EDVAC, ENIAC (updated).

🏆 Importance of Von Neumann Model:

✅ Allowed automatic execution of programs.
✅ Made computers cheaper and easier to program.
✅ Foundation of all modern computers.

📢 Summary:

“The Stored Program Concept allows storing both instructions and data in memory. Von Neumann Architecture implements this idea and defines the basic structure of a computer system.“

📌 Quick Flowchart:

User → Input Device → Memory → CPU → ALU → Output Device
              ↘ (Data & Instructions stored together) ↙

Stored Program Concept- Von Neumann Architecture