All modern Intel and AMD PCs can trace their roots to a single system: the IBM Personal Computer. Originally released in August 1981, this computer became so popular and long-lived that competitors reverse-engineered its BIOS so that their computers could use the same software and peripherals, a practice that eventually resulted in a de facto standard whose descendants we still use today.
If you want to experience what using an old IBM PC was like, you could drop a few hundred dollars on a used one on eBay. Or you could roll the dice on this new oddball laptop on AliExpress. The "Book 8088 [aliexpress.us]" laptop PC combines modern components with an Intel 8088 processor and 640KB (yes, that's kilobytes) of memory.
Update, 5/20/2023: After this story was published, Ars was contacted by developer Sergey Kiselev, who maintains an open-source 8088 BIOS on GitHub. He alleged that the creators of the Book 8088 re-used his BIOS for the system while removing his name and language about the GPL v2 license that the BIOS is distributed under; we can't confirm the claim by comparing the code directly, but there are several distinct similarities in a screenshot Kiselev shared and one used in the Book 8088 retail listing.
"While my work is open source, and I don't mind people using it in their projects, I do care deeply about the principles of open source software development and licensing. And whoever manufacturers this machine, bluntly violates copyright law and licensing," wrote Kiselev to Ars detailing his claim. "Since you start your article with the discussion of how Compaq reverse engineered IBM's BIOS, I think it would be suitable to mention that the manufacturer pirated the BIOS, without crediting the work, and they violate GPL by not releasing the source code of their modified BIOS."