What was it like to be a developer before internet?

We just had fewer resources. We had to be more self-sufficient. Books were more important. I used to spend somewhere between $200 and $500 a year (maybe more!) on reference and tutorial-style books.

CDROMs were the 'downloading' of the 80s and 90s.

NCSA Mosaic just dropped when I was a freshman, but technical info on the nascent internet was sparse enough that you were writing code, poorly, from first principles extracted from books (K&R, Unix Programming Environment, Richard Stevens, OReilly). When you hit a snag, your choices were staring futilely at a manpage, or asking the person sitting in the next carrel.

Back in 1985 when I started I had the original "The C Programming Language", a book from IBM with the various interrupts to access system resources and the "Pink Shirt" book (be Peter Norton).

I once wrote a program in assembler that was 7 bytes long (the executable was 7 bytes) to reset the graphics card.

It was great time to be a "programmer" in those days because you got to try so many different things instead of just cutting and pasting something from the internet. A lot of those things failed and you learn a lot from your failures.

Oh yeah, and there were downloadable ebooks (HTML) in the early day of the web too, when landline connection was measured by connection time (so reading online was expensive as hell).

I learned HTML/JS/CSS, Perl, PHP, Java, C, Linux, etc. all that way, with ebooks. Was a great time before Stackoverflow, when you really learned concepts, not looked for solutions :-)

Bought compilers on disks (or tapes or CD-ROMs).