I was somewhat confusing them with storage tubes per the wiki article title but I didn't realise the tech was still around like that in the 70s! Thought it had gone long before then.

I too was taught to use ed at university and don't consider it time wasted, but I'm well chuffed that better stuff (macs) were coming in then. I actually had the questionable good fortune to use ed on a paper teletype for an hour. Then, staring down at it, my neck cricked and I had to stop.

AIUI ed (or something simpler) on paper teletypes was what original unix might have been written on - good times!

Not.