Microsoft founder Bill Gates speaks during the Global Fund Seventh Replenishment Conference in New York on September 21, 2022.

Microsoft co-founder Bill Gates says that OpenAI’s GPT AI model is the most revolutionary advance in technology since he first saw a modern graphical desktop environment (GUI) in 1980.

Before that, people used their computers through a command line. Gates took the “GUI” technology and based Windows around it, creating a modern-day software juggernaut.

Now, Gates sees parallels with OpenAI’s GPT models, which can write text that resembles human output and generate nearly usable computer code.

He wrote in a blog post on Tuesday that he challenged the OpenAI team last year to develop an artificial intelligence model that could pass the Advanced Placement Biology exam. GPT-4, released to the public last week, scored the maximum score, according to OpenAI.

“The whole experience was stunning,” Gates wrote. “I knew I had just seen the most important advance in technology since the graphical user interface.”

“The development of AI is as fundamental as the creation of the microprocessor, the personal computer, the Internet, and the mobile phone. It will change the way people work, learn, travel, get health care, and communicate with each other. Entire industries will reorient around it. Businesses will distinguish themselves by how well they use it,” he continued.

Gates is the latest big name technologist to take a position on recent advancements in AI as a major shift in the technology industry. He joins former Google CEO Eric Schmidt and former Amazon CEO Jeff Bezos who have predicted that data-based machine learning could change entire industries.

Current CEOs also see major business opportunities in AI applications and tools. Nvidia CEO Jensen Huang said on Tuesday that the field is experiencing an “iPhone moment,” referring to the time when a new technology becomes widely adopted and entrepreneurs see opportunities for new businesses and products.

Gates and Microsoft have close ties to OpenAI, which developed the GPT model. Microsoft invested $10 billion in the startup and sells some of its AI software through Azure cloud services.

Gates suggests that people talking about AI should “balance fears” of biased, wrong or unfriendly tools with its potential to improve lives. He also believes governments and philanthropies should back AI tools to improve education and health in the developing world, because companies won’t necessarily choose to make those investments themselves.