Philips X1100. Maestro used the Philips (Apeldoorn, the Netherlands) X1150 Data Entry system, which was built on a Four-Phase (Cupertino, California) IV/70 processor. A typical configuration at the time of introduction was: System with 96-192 KB RAM 6-24 (dumb) terminals 10- 80 MB disc Magnetic tape Line printer (various types and models were supported) Data communication connection The hardware evolved over time: the Four-Phase IV/70 processor was replaced by the more powerful Four-Phase IV/90 system and more terminals, memory and disc capacity could be supported. The base Philips X1150 Data Entry system was rebranded as Philips P7000 Distributed Processing System as significant additional functionality was added. Software The operating system was a proprietary Four-Phase Disc Operating System (rebranded by Philips) which supported the usual components at that time: text editor, assembler, various compilers, and linkage editor. The Four-Phase software offer consisted of packages for: Data Entry (key-to-disc) 3270 emulation 3270 emulation with programming facilities This unique package allowed the user to include local programming to off-load the mainframe COBOL The original PET/Maestro software made extensive use of existing libraries from the above packages. References External links Christiane Floyd https://web.archive.org/web/20071018125442/http://swt-www.informatik.uni-hamburg.de/people/cfl.html Peter Schnupp to the story of Maestro I IEEE History Center: Ernst Denert Interview (29 June 1993) - Museum of Information Technology at Arlington - Four Phase Four Phase System a multi-terminal display- processing system 1975 software