So here's my vote, taken from my childhood in the mid '80s:

?IO ERROR (and variations thereof)

Picture the following: It's 3am. You're 10 or 11 years old. You have your Radio Shack/Tandy TRS-80 Color Computer 2 plugged into an ancient Zenith black and white TV through an RF switcher saved from a similarly ancient Coleco Pong clone. There is a TRS-80 "Data Cassette Drive" or somesuch named, thinly disguised plain-old audio cassette recorder with a cheap, 99-cent tape in it, storing several of your Extended Color Basic masterpieces (like a program that plays a reworded "When The Saints Go Marching In" or a concentric-circles graphic that looks like a 78 rpm record that took you hours to get just right). A

lt is dark and silent in the world save for the slithering of the tape as you type CLOAD "DECCA78". You think about the mysterious electronic shrieking on the tape which holds the data, set against the tape's unreduced noise like a signal from a faraway shortwave station. The random wow and flutter give the sound of the data stream a creepy half-human quality.

Somewhere in the middle as you watch the prompt cycle patiently through program after program, the terse, impersonal message you've been dreading appears in the blue-gray glow of the TV like a phantom:

?IO ERROR

No explanations, no words of encouragement or advice on how to proceed, just a brisk announcement that your program has lost a battle with the background noise and other defects of a dollar-store storage medium. The tape continues rolling along blindly, like a car with its driver suddenly removed. A ?SN ERROR at least implied that you could go in and fix the damn thing. This, however, was death. You could feel it in the chill under the thermals you used for pajamas.

"Who (the f***) is (this) 'General Failure' – and why is he (/the military) reading my drive?"

That got the techs but moving fast. It still can be seen in some UNIX based OS's