From GCOS 62 to GCOS 4

A preliminary history of the Product Line by Jean Bellec.

This paper does not cover the internal Italian developments that are expected to be described in future documents, but is more focused on the relations between the line and the rest of GE and Honeywell world.


GCOS 62 and GCOS 4 designate a line of products covering the low end of business data processing market offered by Honeywell and Bull from 1974 to the mid-1980s. That product line was developed by and under the responsibility of Honeywell Information Systems Italia, in Milan. The Engineering was essentially located in Pregnana-Milanese.
The first model, that was eventually introduced as Level 62, was successively known internally by the code names E-120 (part of GE APL L-178), B/C and P6.


General Electric and the origin of the Product Line.

The origin of the product line can be traced back to General Electric project of Advanced Product Line in 1968. After having developed the GE-115 in the early 1960s, ex-engineers of Lavoratori Olivetti were assigned by GE product planning to plan the development of the lower end models of APL (code named E-120 at that time).

APL had also a medium range model to be assigned to Bull-GE and a higher model to be developed by Phoenix. APL was lead by John Haanstra, a v.p. of IBM recently hired by General Electric.

The initial intent was to develop a fully compatible line reusing building blocks from a model for the other. Bull-GE had the advantage of having started the design of the medium range system one year earlier than the first formalization of APL. The Bull-GE team might have some feelings of revenge against the Italian who successfully developed the GE-115, while their GE-140 got cancelled. So, the relations between engineering teams started suspiciously. As the APL medium range should be a 32-bits machine, and got microprogrammed peripheral processors for which the French designed a 16-bits minicomputer (eventually known as URC), they propose initially to base the low-end model on the URC hardware and to wind down the Pregnana hardware lab. The Italian response was essentially based on their ability to manufacture the system in Italy at a significantly lower than the French in Angers.

When the French lost this battle in summer of 1968, they lose some interest for developing a common software for the two systems and easily accepted that the low-end software be different. The architecture of the higher models of APL was refined by common teams regrouping Paris and Phoenix teams. This architecture became very ambitious and capable of sophisticated functions similar to those designed earlier for Multics (rings, segmentation, features for multi-tasking…) The Italians, and specifically their Product Planning headed by Marisa Bellisario argued that those features were not needed for the low-end and would seriously penalized the shop cost of the low-end machine. Another argument was that those features were only visible to the operating system that already has been decided as different. In October 1968, HIS Italia presented a E-120 architecture that was a subset of the APL main stream architecture, a proposal that mapped closely the IBM Deutschland 360/20. The approach was approved by John Haanstra and his international team of architects just before the initial APL project plan was terminated in 4Q1968.

During the late GE's years, Paris and Milan refined their APL proposals, going back to a T²L technology, unifying the line of peripherals to be supported. The Shangri-La meeting in Summer of 1969 did not alter the initial plan, accepted that the GE-58 derivative be also considered without any compatibility with other models. The all-azimuths competition with IBM position the B/C Italian model against the 360/20 and validate the previous choices.


The Honeywell NPL and the P6 project.

This plan was taken over and approved by Honeywell in 1970. While the medium-upper range P7/P8 was to be developed by a combination of Boston and Paris, the lower level was developed in Italy under the code name P6. The Level 1 software developed under the Pregnana responsibility was helped by the UK software team of Hemel-Hepstead. The marketing target of the P6 were essentially the card oriented GE-100 ( a large park being in Italy where the penetration of GE-55/58 had been minimal) and a head-on attack on IBM System/3.

Level 1 architecture was characterized by a 8-byte orientation, using the same data types as IBM S/360 as was Level 2. The instruction set was similar but offered indirect addressing. Compared to Level 2, Level 1 presented only 2 segment base registers (one for procedures, the other for data). It did not include a multi-tasking micro kernel (as did Level 2).

P6 processor was a 16-bits wide processor, with a control store (partially in EPROM) that contained microprograms interpreting Level 1 decor and controlling peripheral devices.

Level 1 software, later named GCOS 62, was a disc-based operating system initially centered on batch processing. Card devices were usually ordered, but could be substituted by audio tape cassettes. GCOS 62 also supported low cost open reel magnetic tapes and communication lines.


Level 62

In 1973, the Honeywell NPL was reduced to two base models (P6 and P7) and it was decided to introduce it as a part of Series 60, that also include Phoenix Level 66 (ex-H-6000) and Paris small systems (Level-61). A compatibility umbrella named "Computational Theater" should insure graceful upwards source program conversion between Levels. That was precisely the type of compatibility planned between P6 and P7.

P6 was announced in May 1974 as Level 62 in several marketing models, available immediately from the manufacturing plant of Caluso, Italia.

Level 62 was also licensed by Honeywell to NEC of Japan that renamed the line as ACOS2. Initially, NEC manufactured the P6 model as ACOS System 150.

Level 62 was introduced on a worldwide basis, about 4000 systems were sold between 1974 and 1980.

1200 systems were sold in USA, 1200 in Bull's territories and 1400 in Italy. The Italian park included a larger amount of smaller systems than the other parks (due to the low penetration of GE-58 in Italy, It also includes conversions from GE-115 product line (that in Honeywell-Bull was to be upgraded to Level 64). In other European countries, Level 62 made significant inroads in the small business market. In that segment, the Honeywell offering had the advantage of being more homogeneous than IBM's (System 3 and S/370) The conversion tools from IBM System/3 allowed Honeywell to take over more than 1000 S/3.

GCOS62 was improved thanks to a transactional environment that became one of the strength of the future GCOS4.



In 1978, HIS Italia developed a new processor version of Level 62, code named Gemini. During the development, the IBM announcement of the Series 38 represented a challenging competition, specially for the software. The raw performances of S/38 originally scared HISI designers, but the relative inefficiency of the S/38 architecture interpretation, on the original S/38, reassured them of their ability to compete. The Gemini project was eventually introduced in October 1980 as DPS-4 a strictly compatible system with Level 62.

Among the new features of DPS-4, a conversion tool for GE-58 and batch versions of Level-61 was developed under the form of an emulator and media conversions utilities.

But one of the main features of GCOS4 (the new GCOS62) was a RPG-III language processor and in September 1983 an answer to the relational data base of S/38 that was IDBS4 (integrated data base system) that offered simultaneously RPG-III support and an upgrade path for the Level61 data base system.

The DPS-4 was marketed from 1980 to 1986. 2000 were sold in Italy and 1500 in Bull's territory.

It was not actively marketed in USA . Honeywell sales network was trying to reduce its investment directed to small users.

In Autumn 1979, after the development of the DPS-4 processor, Honeywell pressed HIS Italia and its associated CII-Honeywell-Bull to consolidate the low-end offering, in view to merge the Level 62 and Level 64 product lines. At Castello di Pomerio, HIS Italia proposed to derive from Gemini a central processor able to run GCOS7 as well as GCOS4. This proposal was eventually rebuffed by Paris strategic planning that wanted to secure DPS-7 manufacturing in Angers and that argued that a NMOS DPS-7 processor was in an advanced stage of design and would be ready as soon as 1982, almost as early as the HISI Lucio Pinto's proposal. Actually, it was not until 1987 that a CMOS DPS-7000 system was shipped to customers.

It can be noted that NEC implemented a plan similar to Honeywell's with ACOS 3500 that use exactly the same hardware for the two operating systems ACOS-2 and ACOS-4, while the French never implemented an emulator for a system patterned as a subset of their decor.

HIS Italia architects did not share the enthusiasm of their French and American counterparts for DSA Distributed Systems Architecture. One responsible said that "standards are there to be followed, not preceded". Italians were more occupied to answer its customers requirements, generally influenced by IBM' s SNA than to impose new architecture concepts.

The Level 6 was given more attention as a distributed business computer than was DPS-4. French had embarked in a plan to control their version of Mini-6 and marketed aggressively GCOS 6 among large customers somewhat at the expense of DPS4.



In September of 1986, a last version of GCOS4 systems was announced as DPS/4000. This system used Multibus bus that allowed to mix processors of different origin around a common memory and a commons set of peripherals.

In particular, a 68000 co-processor providing a UNIX (named SPIX-4) environment to GCOS4 customers.

The IBM competition was becoming more aggressive with the re-introduction of System/38 as AS/400 in June 1989. The Italian reacted by reshuffling the DPS/4000 product line by introducing cheaper low-end models and more powerful models with an extended configuration.

The Pregnana engineering had already partially converted to develop a low-end model for the DPS-6 in the early 1980s, designing a single-chip VLSI processor for it, a first in the Honeywell group. Its involvement in hybrid systems gave it the prime responsibility in Honeywell first UNIX systems.

The take-over of Honeywell assets by Bull in the late 1980s confirmed that UNIX assignments and the phasing-out of the GCOS4 product line. The DPS4000 was removed from Bull catalog in September 1992. Around 2000 DPS4000 systems had been manufactured. Italian sales at 1200 dominate the other Bull's markets.



GCOS62/GCOS4 product line was the first of the Honeywell/Bull proprietary product lines to be phased out in the 1990s. It might possible to relate that fate to the initial target of the line: the Small business market. When Honeywell and Bull faced in the 1980s the competition of cheap open systems, they started to retrench from smaller accounts, specially where the park penetration was small (US, Germany, Scandinavia). Whatever merit was recognized to the product line, the overall sales value of the park was small compare to the other GCOS product lines.

GCOS4 failed to address the market of large enterprises distributed systems  that was reserved to Level 6, manufactured in the US and in France, and for which CII-HB and Honeywell made larger investments.
Neither GCOS4 did not received the large support AS/400 received from American and European software houses. Mined internally by the  competition with Level 6 and UNIX systems, GCOS4 systems was not able to resist to IBM AS/400.


Revision : 19 février 2002.