Priority to Level66.

Some Honeywell management views, however, implied a phase- out of Level64 at the profit of Level66 as soon as the G100 and H2000 business sources would have dried up.

Consequences in Japan
A conflict occurred during this period between NEC and Honeywell because NEC had actually decided to make Level64 -- alias ACOS4, its primary product line. NEC seemed to have taken this position because Level64 was locating itself in a 32-bits EBCDIC world which was the world of Japanese big customers and also because the old NEC establishment was very reluctant to unite with TOSHIBA designers who had worked for long with GE on the GE6000 product line. Those differences inside NEC vanish progressively because NEC management succeeded to have a common organization for ACOS4 and ACOS6 product lines with the only exception of the Basic Software Divisions. Nevertheless, Honeywell forced Bull to cancel a new hardware project the P7A, an ECL machine adding a paging architecture to the original 64, which was planned to be developed in Paris in common with NEC in 1973.

Honeywell put also a lot of pressure on NEC to involve it in a new GCOS66 project called the Med-6 project . NEC accepted to work on Med-6, and as an example Yoishi UMEMURA was transferred from Boston to Phoenix on this project. NEC invested later into the ill-fated Med-6 using CML and water-cooled technology which was announced by Honeywell as 66/85 and was later abandoned when faced to performances problems. This design was still imported in Japan without water- cooling and was the ACOS S/800, running under ACOS6. In the mean time, NEC did not abandon any of its developments on ACOS4 and even decided in the early 80s to let this product line overlapping completely the ACOS6 product line.

L66 and Multics
In 1972, it had been decided that the migration path out of the limited decor of the GE600 should be through the MULTICS decor that gave to the 36-bit world similar advanced functionalities as Level64, for segment-level protection and high-level language support.

A coexistence through a GCOS3 accommodation mode under MULTICS, the development of a transaction system à la Level64 TDS on MULTICS decor and the outstanding capabilities of MULTICS interactive facilities - given enough hardware power- would have made a more than reasonable product in 1974. It was also planned to implement a virtual machine project on this system that might have allow a future co- existence of a 32-bit world with a 36-bit world. It was also planned and eventually implemented to have a H2000 emulator on the Level66, but this was provided by the reconnection of a used H2000 to the Level66 system controller and did not imply access to the H2000 peripherals.

The work based on MULTICS decor was a little bit late - like the other NPL projects at the exception of Level62- and W.DIX finally endorsed a proposal of John COULEUR, the original designer of GE600 and GE645 hardware, to introduce a new decor -called NSA as New Six thousand Architecture- instead of following the MULTICS roadmap. The new decor was considering segmentation as data set descriptors and introduced address space as the inter-user protection mechanism; the "ring" concept was dropped for a "domain" mechanism that potentially would avoid the "Trojan Horse" syndrome of user data violation of privacy by procedures planted in the system by some dishonest programmers; it also introduced a progress over NPL implementation: it offered a hardware controlled stack independent from software controlled stack to store registers and return information. This new decor was allegedly to be field retrofittable on existing systems, which was eventually found not feasible, and justified a delay to implement the new facilities. The decision was fought desperately by MULTICS supporters, but Marketing and Management were not clever enough to appreciate the consequences of that decision.

It is not here the purpose of telling the history of GCOS8, but it has to remember that it took 6 additional years to be introduced and that the unification of the segmented environments remains to be seen 14 years later.

follow-on