The silicon metal-oxide-semiconductor field-effect transistor (MOSFET or MOS transistor) did not become significant commercially until two decades after the 1948 announcement of the invention of the transistor by Bell Laboratories. The underlying concept of the MOSFET-modulation of conductivity in a semiconductor triode structure by a transverse electric field-first appeared in a 1928 patent application. It was confirmed experimentally in 1948. However early devices were not practical due to surface problems. Although these were solved at Bell Laboratories in 1958, Bell remained committed to earlier transistor technology. Development of the `other transistor' was first pursued elsewhere. It was finally the needs of computers and the opportunities created by integrated circuits that made the silicon MOSFET the basic element of late 20th-century digital electronics.