John Carmack: Doom, Quake, VR, AGI, Programming, Video Games, and Rockets | Lex Fridman Podcast #309 | Summary and Q&A

August 4, 2022
Lex Fridman Podcast
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John Carmack: Doom, Quake, VR, AGI, Programming, Video Games, and Rockets | Lex Fridman Podcast #309


John Carmack, the renowned programmer behind iconic games like Doom and Quake, discusses his early programming experiences, the value of hard work, and the importance of user value in software development.

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Key Insights

  • šŸŽ® Virtual reality (VR) gaming: The early development of VR games led to a powerful and immersive gaming experience that revolutionized the industry and generated intense reactions from players.
  • šŸ”Œ John Carmack's influence: John Carmack, co-founder of id Software and renowned programmer, played a vital role in the development of groundbreaking games such as Commander Keen, Wolfenstein 3D, Doom, and Quake.
  • šŸ•¹ Transition to artificial general intelligence (AGI): Carmack has shifted some of his focus towards AGI, highlighting his interest in the future potential of advanced AI systems. āŒ› Longest podcast conversation: The interview with John Carmack on the Lux Treatment podcast lasted over five hours, showcasing the depth and breadth of topics covered.
  • šŸ’» First program written: Carmack recalls his early experience writing programs on TRS-80 computers, starting with a simple program that displayed his name on the screen.
  • ļø The value of go-to statements: While go-to statements were primarily used in earlier programming languages like BASIC, Carmack acknowledges their limitations and the importance of structured programming for better code understanding.
  • šŸ’” Love for programming: Carmack developed a passion for programming at an early age, fascinated by the idea of computers following instructions and creating magical experiences.
  • šŸŽØ Early game development: Carmack's early programming endeavors focused on creating video games, starting with text-based adventures and gradually progressing to games with moving graphics, such as a scrolling game inspired by the arcade game Vanguard.


i remember the reaction where he had drawn these characters and he was slowly moving around and like people had no experience with 3d navigation it was all still keyboard we didn't even have mice and set up at that time but slowly moving going up picked up a key go to a wall the wall disappears in a little animation and there's a monster like right... Read More

Questions & Answers

Q: What were John Carmack's early programming experiences, and what moments in gaming history stand out to him?

John Carmack recalls his early programming experiences, starting with his first program on a TRS-80 computer at a RadioShack store. He also remembers the impact of 3D navigation in games and how it revolutionized the gaming industry. One standout moment for him was when he witnessed the startling reaction players had to encountering a monster in one of his games.

Q: How does John Carmack view the value of hard work and its impact on productivity?

John Carmack believes that working hard and putting in more hours can lead to greater productivity and accomplishments. He acknowledges the importance of finding a balance and understanding personal limitations, but he emphasizes that working longer can often result in getting more things done and achieving better outcomes.

Q: What is John Carmack's perspective on the importance of user value in software development?

John Carmack believes that creating user value should be the primary goal of software development. He emphasizes the importance of understanding user needs and delivering products or experiences that provide genuine value. Carmack encourages developers to focus on making the world a better place by creating products that customers find valuable and solve their problems.

Q: How does John Carmack approach work-life balance, and has he made any adjustments over the years?

John Carmack shares that his approach to work-life balance has evolved over the years. He mentions that having children changed his schedule and made him adapt to a more regular work routine. However, he also acknowledges that finding the right balance is individual and depends on personal needs and priorities.

Q: What is the significance of debuggers and IDEs in John Carmack's programming philosophy?

John Carmack emphasizes the value of debuggers and IDEs (Integrated Development Environments) in programming. He expresses his surprise at the aversion to these tools by certain companies and highlights the benefits of using debuggers to gain insights into complex systems. Carmack believes that debuggers are crucial for understanding code and solving issues in large-scale software development.

Q: What role does hard work play in becoming a master or craftsman of a specific skill?

John Carmack believes that hard work and dedication contribute to becoming a master or craftsman in any field. He mentions the importance of putting in the time and effort, allowing oneself to become deeply absorbed in the work. Carmack believes that through hard work, individuals can achieve true mastery and produce high-quality work in their chosen area of expertise.

Q: How does John Carmack view the impact of obsessive dedication on personal relationships and other aspects of life?

John Carmack acknowledges that obsessive dedication to work can potentially impact personal relationships and other areas of life. He understands that not everyone is wired to work in the same way. While he has found fulfillment in his work, he recognizes that work-life balance is a personal choice and that some individuals may prioritize other aspects of life over work.


In this podcast interview, John Carmack, co-founder of id Software and renowned programmer, shares his insights on programming, languages, and creating value for users. He discusses his first programming experiences, the use of go-to statements, falling in love with programming, and the languages he prefers. Carmack also explores the importance of user value and the role of efficiency in programming. He emphasizes the need to focus on creating valuable products and making design decisions based on user satisfaction.

Questions & Answers

Q: What was the first program John Carmack ever wrote?

John recalls the first program he wrote was a simple "10 PRINT John Carmack, I am" on a TRS-80 computer.

Q: Is it bad programming to use go-to statements?

While go-to statements were commonly used in the past, they can lead to chaotic and hard-to-maintain code. However, there are situations where go-to statements are appropriate, especially when certain language features are missing. Carmack mentions that in his current code bases, he rarely uses go-to statements, but they may still be present in low-level programming languages.

Q: When did John Carmack first fall in love with programming?

Carmack expresses that he fell in love with programming at an early age when he discovered computers. He was fascinated by the idea that a computer would do exactly what you told it to, without any backtalk or different point of view. The ability to control these machines and make them perform magical tasks captivated him.

Q: What kind of programs did John Carmack write initially?

Carmack started by learning basic programming, and his early programs included simple games and projects inspired by arcade and Atari 2600 games. He gradually moved toward more advanced programming as he gained knowledge and access to resources.

Q: What was one of the technical hacks John Carmack was proud of in his early programming days?

Carmack recalls a hack he used on the Apple II computers to create scrolling graphics in a game similar to Vanguard. By combining his limited understanding of the hardware, he found a way to scroll low-resolution graphics by manipulating the text screen. This hack became foundational for his future game development work.

Q: How does efficiency in programming impact user experience?

Carmack explains that until recently, efficiency was crucial in game development because computers were not as powerful. Achieving optimal efficiency was necessary to provide a smooth and enjoyable user experience. However, with advancements in technology, the need for extreme efficiency has diminished for many applications, although certain real-time or resource-intensive tasks still require careful optimization.

Q: Can everything be written in JavaScript?

Carmack notes that JavaScript runs a significant portion of the world's systems and has become a powerful and efficient language. While it may not be optimal for all purposes, JavaScript's extensive libraries, portability, and ease of use make it a popular choice. He emphasizes that utilities and tools should be chosen based on their value to users rather than technical preferences.

Q: Can user value be measured quantitatively?

Carmack believes that user value can be measured to some extent, but it is challenging to quantify precisely. He acknowledges the importance of data and metrics but emphasizes the need to balance quantitative analysis with imagination and empathy. Design decisions should consider both data insights and the emotional impact on users.

Q: How can programmers create value for users?

Carmack emphasizes that programmers should prioritize building things of value for users rather than technical achievements or personal pride. They should understand the user's needs and strive to provide a net increase in value compared to alternatives. Balancing resources, making efficient design choices, and focusing on user satisfaction are vital aspects of creating value as a programmer.

Q: Can efficiency and user value coexist in programming?

Carmack explains that there is a constant tension between efficiency and delivering user value. While seeking efficiency is crucial, it should not overshadow the goal of providing value. Striking a balance and avoiding excessive optimization can sometimes lead to better overall results, considering factors such as costs, timeframes, and user satisfaction.

Q: How can programmers make design decisions?

Carmack advises programmers to base design decisions on user value and consider the impact on users' lives. By understanding the needs and desires of users, programmers can make informed choices that prioritize improving users' experiences. Quantitative metrics, qualitative insights, empathy, and imagination all play a role in making effective design decisions.


John Carmack highlights the importance of considering user value in programming. Programmers should focus on creating valuable products and experiences while optimizing efficiency. While quantitative metrics and data are valuable, they should be supplemented by imagination, empathy, and the ability to envision how users will interact with the product. Balancing resources, considering user satisfaction, and making design choices that prioritize value can lead to better programming outcomes.

Summary & Key Takeaways

  • John Carmack reminisces about his first programming experiences and the impact of 3D navigation in early games.

  • He reflects on the value of hard work, working consistently for 60 hours a week and prioritizing user value in software development.

  • Carmack explores the balance between work and personal life, iterating on work habits, and his love for Diet Coke and debugging tools.

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