The International Standards Organisation has accepted that IBM is so far in advance of the rest of the industry with its definitions of the Logical Unit 6.2 and Advanced Program-to-Program Communications, APPC, within SNA that there is no point in trying to create an alternative for the presentation and applications layers of the seven-layer Open Systems Interconnection reference model. IBM has also damped down hosdility by dropping its 1986 demand that ISO accept LU 6.2 and APPC as is or not at all, and is offering free licences to the definitions, and ISO will now draw up a draft international proposal for the two layers based on a sub-set of APPC and some extensions to SNA. The planned draft, currently called Transaction Processing Mode Application Service, will not incorporate the LU 6.2 protocols per se but will use the SNA model, and map its functions onto OSI’s existing service and protocol elements; no user interface will be defined. But the move will make possible transaction processing within a set of distributed applications on incompatible machines. This has only been possible in single remote applications outside LU 6.2. Siemens, Bull and IBM itself are working together to produce the draft international proposal in time for the next meeting, to be held in Tokyo in June. It is hoped a firm standard will be estabished a year later, in 1988. The system being defined by Siemens, IBM and Bull must be compatible with the Remote Operating Services, ROS, subsystem that has been in development at the European Computer Manufacturers Association, and must also co-exist with Standard Program-to-Program Communications, SPPC, for remote and distributed database access. A co-operative attempt between ICL and Siemens to produce an alternative to LU 6.2 ran aground in the summer of 1986, says Herbert Donner, head of the European Standards Promotion and Applications Group, SPAG. It would have taken us until 1990 to produce a working product and what would have emerged would have been similar to APPC. The IBM concessions mean that it will have no overall control of the product that develops.
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