It really was. I had a computer with 16 MB RAM and Opera was basically the only browser that worked on it. The back button was instant in a way nothing has ever been again.
They had some kind of intermediate representation of page renders that was efficiently cached on disk so that it made zero network requests on history navigation. I suspect this same approach also played a part in facilitating the fulltext history search feature I've also never seen in a browser since.
I'm guessing with the way web standards have evolved & become more complex this might actually be impossible to do today while remaining compliant - honestly give me non-compliance though.
True! Came to post the same thing - one of my favourite feature of Opera Presto engine was how all the websites in your history was also "indexed" locally, so that you could do a simple keyword search on "History" to find the web page you wanted to re-visit. It was fast and accurate and made it a breeze to find any site in that you had browsed and was still cached, and it was an incredibly useful feature.
Yeah, I don't know, I don't see how you can't pause execution and store the entire interpreter state and DOM somewhere. Maybe it's just that nobody cares enough to go through all the effort?
Modern pages would also likely be much more touchy about the imperfections of such a mechanism. A lot of “old browsers good” in general seems to be about modern webdev, not modern browsers[1].
I'm guessing with the way web standards have evolved & become more complex this might actually be impossible to do today while remaining compliant - honestly give me non-compliance though.