Bolt, Beranek and Newman Superseded
Acoustics consultants who built the ARPANET's IMPs, wrote TENEX, and sent the first email with an @ sign. Absorbed into Raytheon in 2009.
MIT acoustics professors Bolt and Beranek founded BBN in 1948; it became ARPA's computing contractor of choice. Its engineers built the IMPs — the ARPANET's packet switches — in 1969; Ray Tomlinson sent the first networked email (@ sign) there in 1971; TENEX gave the PDP-10 a virtual-memory OS.
Later acquisitions folded BBN into GTE, then Verizon; Raytheon bought it in 2009 for ~$350 million. The name survives as RTX BBN Technologies.