Cylinders -> discs

“You would hire, say, a brass band, which you would surround with a phalanx of recording machines loaded with blank discs…”

Oops !

Hey, a disk is a cylinder, so a cylinder can be a disk.

Indeed, a disk is but a quite squat cylinder.

Topologically speaking, cylinder = disk. Cecil always speaks topologically. Chill out, dude.

Topologically, a donut is a picture frame. Don’t go too far.

From the OED.

Yahbut Cecil is talking about cylinders–says so later in the paragraph.