My first assembler was pirated from an Intel 8080 development system. I printed the hex dump on an ASR33 teletype and entered it by hand into my SOL80. I hand edited the I/O functions to use the SOL's cassette drive.
The SOL80 was build from a bag of 74LSxx parts and an 8080.
I relocated the SOLUS monitor from $C800 to $F800 so I'd have more room to run a (modified) UCSD Pascal system.
I don't think that hex editors existed back then. At least I didn't have one.
I wrote my first C compiler to run in 48K of memory: 5 passes: pre-processor, parser, improver (not really), code generator, and assembler. For the 6809. Yes, floating point in software and divide as well.
I ran (almost) version 7 Unix on a PDP11/23 (Venix), with a compiler written by Ritchie.
I ran BSD Unix on a VAX. With a 9-track tape drive.
I had a SparcI, a Lisa, the original Mac.
That was in the first 5 years. A lot happened since then.
You guys (at least some of you) have missed a lot.