Most of that software is still in use because it's very poorly written using a combination of COBOL and assembler and people are afraid to touch it.

Very poorly written and it works, at least.

I'm currently reading a book written in the 1170s, so I can imagine that :)

And I've just finished the Iliad (in translation) which dates from about 800BC describing events of ~1250BC.

It's a bit like the descendants thing that was discussed a few days ago on here - either lots of stuff will survive the next 1000 years (and therefore lots of running code will) or almost nothing will.

There are some technologies out there in the non-mainframe world that have similar properties.

To name the ones I know of - vi, emacs, C, Common Lisp. These have held pretty steady for about 30 years now.

Given I'm sure many people here have anecdotes about little snippets they wrote in a short amount of time that ended up in use for a decades, even though the code was crappy (someone tell me I'm not alone here...) - I'd be willing to bet something, somewhere will still be around a long time from now.. though a thousand years is a bit hard to comprehend in terms of technological change.

If banks still exist they'll still be emulating zOS on their quantum dimension-folded computers...

Cool? I'd think that would be depressing.