[norwayjose]

I started my career as a field engineer (basically a computer mechanic) on mainframes and minicomputers 47 years ago. For the first 13 years, almost every computer I worked on had front panel switches and lights which was great for writing and debugging tiny diagnostic programs. I wrote those diags directly in machine code because I had the CPU instruction manuals, no access to an assembler, and a fair amount of free time when I worked a midnight shift on call. I'd sit at a desk, writing the machine code on lined paper because the sites I worked at rarely had graph paper in the supply cabinet. At first I had to look up the op codes for the instructions I wanted but I was able to memorize the ones I used most often which made it a quicker process. The fun part was using the toggle switches to enter those instructions and finally to start it running.

After 6 years of being a field engineer and writing exclusively in machine language, I made the switch to being a systems analyst which gave me access to an assembler. That seemed easy after having to calculate relative jumps/subroutine calls for so long.