What does Glassfet mean?
Glassfet is a slang or retro tech term that refers to a type of vacuum tube that was commonly used in computers until it was replaced by transistors in the 1960s and integrated circuits in the 1970s. It is based on MOSFET, the acronym for metal–oxide–semiconductor field-effect transistor. However, unlike MOSFET, Glassfet is a colloquial, rather than technical, term.
Techopedia explains Glassfet
In addition to its emergence from the MOSFET tube, experts in the field of emerging vacuum tube technology also refer to a gallium arsenide field effect transistor (GaAs FET) as something that led to the emergence of the glassfet term. Looking at the situation in detail, experts have noted out that glassfets as a type of MOSFET are very different from GaAs FET, in terms of size, voltage and other properties.
Glassfet is part of a technology largely followed by hobbyists. The emergence of flat-panel screens and light-emitting diode (LED) technology has rendered the use of some types of vacuum tubes obsolete. However, others point out certain vacuum tube properties, such as the ability to carry an impulse faster than solid-state transistors, and refer to new programs to create vacuum tubes on a nanoscale. This suggests that these smaller, more nimble varieties will continue to power future technologies. For its part, the term glassfet survives as computing slang, along with many other terms of the same era.