# History and Acknowledgments

"There are lots of interesting problems in window systems", said Butler Lampson to Greg Nelson in April, 1984; and he was right. Nelson was enticed into the design meetings for the new window system for the Firefly multiprocessor at SRC. In 1984 most of the discussions were about what came to be called the event-time protocol, and besides Lampson and Nelson the main participants were Mark R. Brown, Jim Horning, and Lyle Ramshaw. Mark Brown and Greg Nelson wrote the first version of the VBT interface.

Mark Manasse joined SRC in 1985, and he and Nelson finished the design and implementation of the first version of Trestle (then called Trellis), which they shipped for use at SRC on December 31st, 1985.

Trestle evolved for five years, improving under feedback from the projects that built upon it, notably Luca Cardelli's Dialog Editor, Mark R. Brown's Ivy text editor, Marc H. Brown's FormsVBT system, Patrick Chan's session manager Rooms, and a number of applications built by Andrew Birrell. Bob Ayers's Facade system spurred the Trestle team into performance work that otherwise might never have been undertaken.

In 1990 and 1991, Steve Glassman, Mark Manasse, and Greg Nelson overhauled Trestle to make it into the portable Modula-3 X toolkit described in this reference manual. We are grateful to the Modula-3 export sites that used the alpha-test version of the system released in January 1991; special thanks for the helpful feedback from Dave Goldberg, Norman Ramsey, Jim Meehan, and Marc H. Brown. Finally, we thank Patrick Chan, James Mason, and Jim Horning, who carefully read the entire reference manual and made many helpful suggestions.