Thomas Edison demonstrated his invention, the Phonograph, for the first time on 29th November 1877. The inventor had announced it a few days back. The Lost Chord by Arthur Sullivan, one the oldest known sound recording that has survived to this day, was on the phonograph.
FYI, it’s now universally agreed upon that the oldest known sound recording is that of someone singing a French folk song, Au clair de la lune, on
Édouard-Léon Scott de Martinville’s Phonautograph.
The origins of phrase "Hello world!" as a test phrase can be traced to an example program in seminal book, "The C Programming Language", written by Brian Kernighan and Dennis Ritchie. [more...]