I found mention of Cadmus CadMac Toolbox/PCSMac when reading more about the RT PC. It is interesting that this would later be sold to Apple. Something not often mentioned in histories of PCS, Cadmus Computer Systems or Apple. "Cadmus Computer Systems had created the CadMac Toolbox, a Macintosh Toolbox implemented in C on a UNIX base), and under a special agreement with Cadmus, we received a license to port the CadMac code from their hardware base to the RT" Norman Meyrowitz - Intermedia: The Architecture and Construction of an Object-Oriented Hypermedia System and Applications Framework https://dl.acm.org/doi/10.1145/28697.28716 A video presentation of Intermedia and CadMac running on IBM ACIS' port of 4.2BSD for the RT PC, with kernel changes https://vimeo.com/20578352 they later moved to A/UX on the Macintosh II InfoWorld 13 Jun 1988 https://books.google.com/books?id=-T4EAAAAMBAJ&pg=PT11 'Meyrowitz: It was before Apple Unix. There was a workstation company called Cadmus that was producing workstations largely for CAD and Tom Stambaugh took the Macintosh APIs and reprogrammed them to run on Unix workstations. We went up to Cadmus and convinced them to license that to us for the university. We were using Mac APIs on Unix systems because we wanted systems that supported the network file system, that had virtual memory, that had bigger disks. So we did that and it was a beautiful system. Eventually, convinced Apple to create a A/UX [Apple Unix] which was a Unix system and we ran on that. Cadmus went out of business, and we had the only license to CadMac, and Apple wasn't that happy to have it around. We had actually convinced them that they should release it to universities, because having that API around, especially if they could sell it to other companies to put it on their workstations, could actually be lucrative. We almost convinced them to do that. We were actually having a celebratory dinner at McArthur Park in Palo Alto to celebrate this and then Jean-Louis Gassée walked in and said, "The deal is off."' Oral History of Norman Meyrowitz http://archive.computerhistory.org/resources/access/text/2015/05/102658326-… "we chose the Apple Macintosh front-end, or rather our local version thereof (CadMac, now PCSMac) which was available on the Cadmus 9000 computers." https://quod.lib.umich.edu/cgi/p/pod/dod-idx/development-of-an-intelligent-… "Apple Workstation Efforts Get Boost from Cadmus Although Apple Computer Inc, won't say so, industry analysts believe the company's acquisition of software technology from Unix workstation maker Cadmus Computer Systems may speed up the introduction of high-end Unix workstations from Apple. ... At Apple's analysts' meeting April 23, chairman John Sculley said Apple had acquired the rights to the technology from Cadmus of Lowell, Massachusetts, to use in long-term advanced product development efforts for the Macintosh. He said the Cadmus software would help the company develop a workstation for the engineering community and federal government markets, which use Unix-based systems, according to Apple's transcripts. Although Sculley has not detailed what Apple will do with the Cadmus technology, Cadmus introduced last summer a graphics workstation equipped with Cadmac, a graphics environment that is compatible with Apple's Macintosh graphics routines." InfoWorld 19 May 1986 https://books.google.com/books?id=SS8EAAAAMBAJ&pg=PA3