How an Amateur Ran a ChatGPT Client on an IBM PC in 1984


WTF?! OpenAI’s ChatGPT may represent an advanced artificial intelligence technology, but the end user’s experience with it is nothing more than text and a network. One modder decided that with a little effort, a 39-year-old PC would have everything it needed to run a generative AI text client.

Amateur Yeo Kheng Meng recently introduced his ChatGPT client for MS-DOS running on his IBM PC, which is almost 40 years old. The application composes the text as well as the OpenAI service in modern systems, only in the form of simple text in a retro style.

Yeo chose the oldest MS-DOS PC in his collection — the IBM 5155 laptop PC from 1984. ram. Yeo believes that any machine with DOS should be able to handle everything that works according to these specifications.

Creating new software for the Internet on an operating system before the Internet and a PC is fraught with many problems. Yeo needed to figure out how to run a network in MS-DOS and test the IBM PC software on a modern computer. Testing the client on a 64-bit Yeo machine with Windows 11 turned out to be difficult because by default it cannot run compiled 16-bit DOS binaries. Porting the test code to an IBM PC would significantly slow down development.

In addition, compatibility with winevdm did not allow connecting to the network. Python for MS-DOS also cannot be used because it does not support 16-bit processors. Instead, Yeo tested the project on a Virtualbox system with the same DOS version installed on 5155, with a network bridged to the host computer.

Yeo said the MTCP library—a scalable TCP stack compatible with multi—core processors at the user level-was the most important tool in the project. This allowed him to program network functionality relatively quickly, although he had to write about the lack of multithreading in DOS.

The only part of the ChatGPT client that does not initially work on the IBM system is the HTTP—to-HTTPS proxy server. Even if Yeo could transfer the necessary TLS library to Intel 8088, its performance would most likely be too low. Thus, this part of the process must be performed on a modern PC.

Even if this is not a completely clean solution, the use of generative text AI in such an old system carries a somewhat retrofuturistic atmosphere. Typing and getting an intelligent response is what humans have imagined for computers since at least the heyday of 5155.

The project also resembles other examples of modern functionality running on retro hardware. In 2015, Netflix engineers created a client for the NES. In 2019, Yeo released a version of Slack for Windows 3.1, and in 2021, someone got an Apple IIe to play fullscreen video.


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