Piano rolls were made from recorded performances. A pianist would sit at a specially designed recording piano and the pitch and duration of notes played would be either marked or perforated on a blank roll of paper, together with the duration of the sustaining and soft pedals.
For playback on a player piano, the roll moves over a device known as the 'tracker bar', which first had 58 holes before being expanded to 65 and then 88 holes. When a perforation passes over the hole, the note sounds.
Piano rolls were first used around 1897.
MIDI files accomplish digitally and electronically what piano rolls do mechanically. In addition, software for listening to and editing a performance stored as MIDI data often has a feature to show the music (for example, in a piano roll) in score.
Among the historic piano rolls scanned into MIDI for kunstderfuge.com are Artur Rubinstein and Sergei Rachmaninoff playing various transcriptions; Jozef Hofmann playing Beethoven's Rondo a Capriccio and the "Moonlight" Sonata; Ignaz Paderewski playing the "Moonlight" Sonata; Vladimir Horowitz playing Chopin's Waltz in F Minor; Pietro Mascagni playing a transcipton of the Intermezzo from Cavalleria rusticana; and recordings by Ferruccio Busoni, Wilhelm Backhaus and Myra Hess.