The outer layers are made of acrylic plastic and the vacuum chamber in the middle is divided into three or four watertight compartments stacked on top of one another.

ECONOMIST: Cataracts

But it is possible to lay down a thin layer of silicon on a flexible plastic sheet, through a process called vacuum deposition.

ECONOMIST: Just press print

However with the introduction of lighter weight and more flexible plastic substrate magnetic tapes, combined with a vacuum column to control the tension that the magnetic tape experiences during use, the IBM 726 was a prototype of the modern digital tape recording system.

FORBES: Magnetic Tape Turns 60