GE-600 series
When GE left the mainframe business, the line was sold to Honeywell, which built similar systems into the 1990s as the division moved to Groupe Bull and then NEC.The CPU could hand off short programs written in the channel controller's own machine language, which would then process the data, move it to or from the memory, and raise an interrupt when they completed.This allowed the main CPU to move on to other tasks while waiting for the slow I/O to complete, a primary feature of time sharing systems.GE supplied the hardware to the project and was one of the development partners (the others were Massachusetts Institute of Technology and Bell Labs).GE saw this project as an opportunity to clearly separate themselves from other vendors by offering this advanced OS which would run best only on their machines.The GE-600 line of computers was developed by a team led by John Couleur out of work they had done for the military MISTRAM project in 1959.The Air Force required a data-collection computer to be installed in a tracking station downrange from Cape Canaveral.However, by the early 1960s GE was the largest user of IBM mainframes,[5] and producing their own machines seemed like an excellent way to lower the costs of their computing department.In one estimate, the cost of development would be paid for in a single year free of IBM rental fees.Many remained skeptical, but after a year of internal wrangling, the project to commercialize the M236 eventually got the go-ahead in February 1963.While most were single-processor systems, the 635 could be configured with four CPUs and up to four input/output controllers (IOC's) each with up to 16 Common Peripheral Interface Channels.In August 1964, IBM considered the GE 600 series to be "severe competition in the medium and large-scale scientific areas".The new GE-655 replaced the individual transistors from the earlier models with integrated circuits, which doubled the performance of the machine while also greatly reducing assembly costs.Besides MIT, Bell Labs, and GE, GE-645 systems running Multics were installed at the US Air Force Rome Development Center, Honeywell Billerica, and Machines Bull in Paris.