sentences:  Capacitors had also been used for earlier memory schemes, such as the drum of the Atanasoff–Berry Computer, the Williams tube and the Selectron tube.The invention of the MOSFET (metal-oxide-semiconductor field-effect transistor), also known as the MOS transistor, by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959, led to the development of metal-oxide-semiconductor (MOS) DRAM.In 1966, Dr. Robert Dennard at the IBM Thomas J. Watson Research Center was working on MOS memory and was trying to create an alternative to SRAM which required six MOS transistors for each bit of data.