futurebus was the source of some of the original work on cache coherency, live insertion of boards, and trapezoidal transceivers. trapezoidal transceivers have a controlled risetime and make backplane and bus design much simpler. the original trapezoidal transceivers were made by national semiconductor. newer futurebus+ transceivers that meet the ieee std 1194.1-1991 backplane transceiver logic (btl) standard are still made by texas instruments. futurebus+ was used as the i/o bus in the dec 4000 axp and dec 10000 axp systems. futurebus+ fddi boards are still supported in the openvms operating system. futurebus+ custom chips support advanced symmetric and asymmetric versions of unix-like operating systems supported by companies such as american logic machines.