Last Wednesday Eric Raymond (ESR) wrote a blog post noticing that younger engineers no longer understood the ASCII code set at the bit level and didn’t understand what many of the non-printable characters were for. He speculated that this was a result of the demise of RS-232 terminals in the early 1990s. When the traditional (not USB) serial interface all but disappeared the meaning of most of those special characters and how to generate them from the keyboard were no longer core knowledge that every hacker had to know.
As a followup to the post, ESR has written a short article on Things Every Hacker Once Knew that tells the story of what the various special characters were used for and describes their hardware context. If you don’t have a bunch of gender benders and a breakout box gathering dust in your (hardware) toolkit, you probably don’t know most of what’s in the article and you should definitely give it a read. Not only is it interesting, it’s a part of our culture and we should all be at least dimly aware of it.
As ESR says, although there are a few vestiges of things like the DLE character still being used mostly it’s not something today’s engineer will need to know. Still, it is worth knowing if only so you don’t have a moment like this
OH MY GOD
YOU DIAL A PHONE
BECAUSE THE FIRST ONES HAD A CIRCULAR DIAL
I NEVER CONNECTED THIS BEFORE
— SwiftOnSecurity (@SwiftOnSecurity) January 27, 2017