On: 50 years of eBooks: 1971-2021

A noteable achievement, but it doesn't contradict the article. Perhaps HP100LX fits your definition of an eBook and the prior work does not, can you explain why?

Total replacement of the concept "book". Fits into your pocket and so on.

10 Megabytes was the maximum disk at the time of 1992 costing 1000 gringo dolares. With careful zipping it was hundreds of books.

The Sony Data Discman predates the HP by years. This is about eBooks as a concept/file and what Project Gutenberg was doing and not readers anyways.

I tried that too. It was just horrible. If we drop the pocketable feature, Data General One was quite good ebook. It was 1982 maybe.