I don't go back quite that far professionally -- I guess my first official software job was in 1996. My perspective was a little different because I was in biotech at the time, not in an actual software company. But we had in-house dedicated software people, and we worked with a lot of contractors, so I guess I'm going to pile on here.

1. Processes: mostly, winging it. But since I worked in a regulated industry, there was a lot of very specific stuff the Feds expected of us; and almost no internal documentation to get someone up to speed on it. Downside was you often did stuff wrong once before some Senior (which in those days meant more than a couple years out of college) made you do it again. But this was part of learning, and I'm sure they learned it that way too.

2. Design Principles: um, mostly winging it, but I'm sure it was less freewheeling in parts of the company like manufacturing. For those of us working mostly with data, we were all very interested in outcomes, and some of us cared a lot about the users, but a lot of the software was solving problems that had never been solved with software before, and we made a lot of it up as we went along. Towards the end of my first job I went to a big HCI conference and thought, hmm, there is a lot of jargon and long-winded academic presentation going on -- but is anyone outside the bubble listening? (I guess OS designers were listening, and I thank them for their sacrifice.)

3. Work-life balance: we worked hard, and yes we played hard (not just the young) -- but it was pretty much in line with everyone else in the SF area working in high-energy industries at the time. There was no expectation of better or worse working conditions if you were doing software versus anything else you might do. You had an office if your peers had offices. Then later, with the startup craze, all-nighters and lofts and so on came into vogue, but that was self-inflicted (and at that age, I really enjoyed it).

4. Compensation: we got paid as much as the other professionals, and not more, but usually also not less for our relative place in the org charts. It was nothing like the situation now, where there are maybe a dozen professions that get way higher pay than their equals in other professions; nor was there such a big gap between the US and other rich countries. But then, SF was a cheap place to live back then. Much changed and it changed fast. (For one actual data point: when I finally made it to "official computer guy" was when I started making more than my local bartender, who until then had made the same as me but only worked three nights a week.)

And as a general riff:

Almost nobody was in it for the money, which is not to say nobody was trying to make a lot of money. Rather, everybody I encountered who was doing software was more or less destined, by their talents and affinities, to be doing software at that moment in history. The people who were primarily about the money got out of coding as fast as they could, and did management or started companies, and that was for the best.

Everything was magical and new magic was being invented/discovered every day! I myself got to go from working on character terminals to Macs to Irix and back to Macs again; to discover Perl and write ETL programs as what was then a "junior" -- but in today's world would probably be a "senior" because I had two years' experience. I would read man pages like people read (used to read) encyclopedias, which is kinda what they are. I had a housemate who would get high and write what we would now call the "AI" of a famous video game. I wrote my first CGI programs on a server at best.com. Every step that now seems mundane was, at the time, amazing for the person taking it for the first time -- writing a crappy GUI! client-server! relational databases! friggin' Hypercard! A friend was given a do-nothing job and became an expert at Myst before he quit, because... magic!

The path from writing code to business outcomes was a lot shorter than it is now, and I speculate that this put a limit on the gatekeeping attempts by folks with whatever "elite" degrees or certificates were in vogue.

And there were a lot more people (relatively speaking) who came from different backgrounds and, like me, had found themselves in a time and place where "playing with computers" suddenly was part of the job, and a springboard from which to grow into what we eventually started calling, correctly IMO, Software Engineering.

But back then, in biotech and in the bright shiny new Internet world I joined around 1998, boy oh boy was it not Engineering. It was inventing! It was hacking! And it was a lot of fun.