Williams tube
In June 1952, Daniel Slotnick began working on the IAS machine at the Institute for Advanced Study (IAS) at Princeton University. The IAS machine featured a bit-parallel math unit that operated on 40-bit words. Originally equipped with Williams tube memory, a magnetic drum from Engineering Research Associates was later added. This drum had 80 tracks so two words could be read at a time, and each track stored 1,024 bits.