Back when I started programming computers came with circuit diagrams and listings of their firmware. The early machines I used like the Sharp MZ-80K, the BBC Micro Model B, the Apple ][ and so on had limited instruction sets and an 'operating system' that was simple enough to comprehend if you understood assembly language. In fact, you really wanted to understand assembly language to get the most out of these machines.
Later I started doing embedded programming. I wrote a TCP/IP stack that ran on an embedded processor inside a network adapter card. Again it was possible to understand everything that was happening in that piece of hardware.
But along the way Moore's Law overtook me. The unending doubling in speed and capacity of machines means that my ability to understand the operation of the computers around me (including my phone) has long since been surpassed. There is simply too much going on.
And it's a personal tragedy. As computers have increased in complexity my enjoyment of them has plummeted. Since I can no longer understand the computer I am forced to spend my days in the lonely struggle against an implacable and yet deterministic foe: another man's APIs.
The worse thing about APIs is that you know that someone else created them, so your struggle to get the computer to do something is futile. This is made worse by closed source software where you are forced to rely on documentation.
Of course, back in my rose tinted past someone else had made the machine and the BIOS, but they'd been good enough to tell you exactly how it worked and it was small enough to comprehend.
I was reminded of all this reading the description of the Apollo Guidance Computer. The AGC had the equivalent of just over 67Kb of operating system in ROM and just over 4kb of RAM. And that was enough to put 12 men on the moon.
Even more interesting is how individuals were able to write the software for it: "Don was responsible for the LM P60's (Lunar Descent), while I was responsible for the LM P40's (which were) all other LM powered flight". Two men were able to write all that code and understand its operation.
12 men went to the moon using an understandable computer, and I sit before an unfathomable machine.
Luckily, there are fun bits of hardware still around. My next projects are going to use the Arduino.