Computer Standards & Interfaces 15 (1993) 119-120 119

North-Holland

Guest editorial

The objects are coming!

William Kent Hewlett-Packard Laboratories, Palo Alto, California, USA

The objects are coming! The objects are com- ing! Big ones, little ones, fat ones, skinny ones, round ones and square ones. They 're on our screens, in our networks, at our interfaces, and in our methodologies. No programming language is complete without them. They're all over our conferences, workshops, journals, magazines, newsletters, and bulletins. They've even found their way into the weekly news magazines and the Sunday supplements.

But what is an object? Well, everybody knows that, of course. An object is 'really' an applica- tion. An object is 'really' a coherent chunk of data and code all in one place. An object is 'really' an active agent in your system. An object is ' really ' something that sends and receives mes- sages. An object is 'really' something that repre- sents a single thing or concept in the real world. An object is 'really' something you can see on your screen. Are these all the same idea? Not exactly.

So what are they, really? That ' s the sixty-four dollar question that makes this issue of Computer Standards & Interfaces so timely. As usual, the problem isn't that we don' t have an answer - we have too many. That ' s why the need for standard- ization is so strong, and also why it's so hard to achieve. Again, it's not that we don' t have emerg- ing standards - we have too many. Dozens of groups and committees are defining ' the ' object model for their language, interface, methodology, etc.

Correspondence to: W. Kent, Hewlett-Packard Laboratories, Palo Alto, California, USA, email: kent(~,hplabs.hp.com

That 's the challenge facing X3H7, the new A N S I / X 3 Technical Committee dealing with Object Information Management. Formed early last year in response to a recommendation of the Object Oriented Database Task Group ( O O D B T G ) of the A N S I / X 3 / S P A R C Database Systems Study Group (DBSSG), X3H7 has the mission of harmonizing the object-oriented as- pects of standards developed by other commit- tees.

This is a unique and unusual mission. Though we are chartered to produce a reference object model description, that 's not our most important product. The real product is intangible, reflected indirectly in the standards produced by other groups. To the extent that such standards are consistent, X3H7 will have accomplished its basic mission.

How will we achieve this? What does 'harmonious ' really mean? X3H7 is new enough that we can still say we're trying to figure that out. But we have some definite ideas.

For one thing, there is a spectrum of solution styles. At one unlikely extreme we have a single unified object model that suits all needs. At the other extreme we have architectural frameworks allowing facilities which use a plethora of object models to interoperate with each other. The real solution is undoubtedly some hybrid. Essential to it all, though, is some uniform and consistent description of all object models.

X3H7 is not in the business of prescribing the ' r ight ' object model. We are collecting descrip- tions of a variety of object models into a ' features matrix', which will be synthesized into a single

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120 Guest editorial

description that is consistent in its goals and technology, described in a consistent manner .

Interoperabi l i ty problems themselves come in various flavors. We are s tructuring these into a problem space with at least the following dimen- sions: • 'Hor izon ta l ' interactions between peer applica-

tions, e.g. be tween an editor, a layout manager , and a pr inter program.

• 'Ver t ical ' interactions between software in dif- ferent system layers, e.g. GUI , editor, ORB, DBMS.

• 'Life-cycle ' interact ions in the time dimension, e.g. between facilities for analysis, design, com- pilation, debugging, execution, etc. Ideally, X3H7 should proceed serially, first

learning the current state of object technology f rom the work of o ther groups and the published literature, then synthesizing it all into a coheren t strategy and recommendat ions , and finally trying to guide o ther groups toward a c o m m o n goal. In reality, we are const ra ined by the same acceler- ated ' t ime- to-marke t ' as everyone else, and so we

are tackling all those stages simultaneously. X3H7 has under taken a substantial mission, and your help is solicited. For more information, contact Liz Fong [(301) 975-3250/fong@ecf.ncsl .nist .gov].

Whe the r or not you join us in X3H7, this issue of Computer Standards & Interfaces provides a valuable introduct ion to the problems we are addressing.

Bill Kent is with the Database Tech- nology Department at Hewlett- Packard Laboratories in Palo Alto, California, researching object-ori- ented data models. Bill played a lead- ing role in developing the Iris proto- type object oriented database system, and is currently active in the Pegasus project, investigating interoperability of heterogeneous database systems. Bill is the author of the book Data and Reality and numerous papers in the area of data analysis and design,

conceptual schemas, entity-relationship models, the relational data model, and object technology. Bill chairs the new ANSI X3H7 committee on Object Information Management, and was acting chair of the ANSI/SPARC DBSSG Object Ori- ented Database Task Group. He is active in the Object Management Group's Technical Committee, Object Model Subcommittee, and Database Special Interest group. Bill is also a member of IFIP TC2.6 (Data Bases).