In or around 1966, the Univeristy of Michigan obtained an IBM 370 mainframe. Unfortunately, there was no operating system for the machine, so the programmers decided to write their own. Thus was born the Michigan Terminal System (MTS). It was one of the first systems in the world to provide an avenue for sharing information and ideas by enabling electronic communications over networks. Originally run on the mainframe computer system housed in the North University Building (NUBS), in the 1970s it was moved to the newly-created North Campus in the new Computing Center building.
Several other universities around the world expressed interest in MTS, and a consortium of universities was formed (the "MTS Consortium"). At its peak it consisted of thirteen universities in the United States, Canada, and the United Kingdom.
Over time, the hardware changed to the IBM 3090 series. When I was in school there, the IBM 3090-400 was upgraded to an IBM 3090-600E, the two distinct systems ("UM" (maize) for faculty, staff, and the government; "UB" (blue) for students and faculty) were merged into one, the last card reader was taken offline forever, and cartridge (3480-format) tape drives were added. One of the three campus Xerox 9790 Page Printers was decommissioned (from the Michigan Union), leaving one on Central Campus (at NUBS) and one on the North Campus (at the Computing Center building).
On June 30, 1996, the University of Michigan ceased operating MTS on the IBM 3090. By this time, all services had moved to client/server-based computing, typically on Unix boxes for servers and various Mac and PC and Unix flavors for clients. Many departments had created their own IT infrastructure aside from the University-provided Information Technology Division (ITD).
On May 30, 1997, the University of MIchigan shut down the MTS system for the last time. The announcement of the retirement is available.
A more detailed history is available in the Overview section.