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>From ellis@osf.org Sun Aug 16 11:25:17 1992
Date: Sun, 16 Aug 92 12:15:27 -0400
From: ellis@osf.org
To: gaiawork@osf.org
Subject: GAIA issues
In preparing for the GAIA workshop, we've put together a list of questions and issues, generated internally and from your responses. At the workshop, we expect many additional issues to be generated.
During the workshop, we will address many of these issues. In some cases, answers will emerge; in others, we hope to at least understand how answers will need to be determined by the GAIA team.
-- Ellis
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General Issues ==============
What are the key objectives of GAIA With respect to the enterprise? With respect to the user? With respect to the developer? With respect to the system vendor? Other?
Timeline What is the urgency of GAIA? What factors drive the urgency? What elements of GAIA need to be available when? What are the key events that influence the timing?
Minimum requirements/deliverables What are the standards/prerequisites on which GAIA should be based? (pros/cons) What are the key features/characteristics of the solution? Must some or all of the GAIA specification be backed by a definitive, sample or reference implementation? What is the minimum set of deliverables needed to be successful?
OSF role vs. role of others What aspects of GAIA is OSF best equipped to deliver? What other players in the industry are in a position to deliver part of the solution? How and where do vendors/ISV's add value?
Business and Process Issues ===========================
Industry segmentation What are the target platforms: windows, OS, network, other? How are the target users? What are the target industries?
Value "allocation" What is the relative value of GAIA components to each constituency?
Potential structure/packaging Which components might reside locally, and which remotely? How might these components be licensed? Is this technology appropriate for shrink-wrapping?
Process preferences What is the preferred process for implementing the deliverables? What model for technology acquisition is most appropriate? How should OSF handle non-vendor-neutral elements of GAIA, e.g. gateways to alternative frameworks?
Underlying Storage and Transport Infrastructure ===============================================
Is a standard file system adequate as the storage medium, or must an intrinsically typed persistent object store be used? Is CORBA an appropriate implementation infrastructure? Regardless of the implementation strategy, should IDL be used to specify GAIA service interfaces? Is CORBA functionality adequate, especially with regards to inter-ORB interoperability, and federated naming? What is the relationship of naming in GAIA to existing standards (e.g. X.400 directory services)? What are the pros and cons of using DCE directly for distributed communication and naming, especially in the short term? What are the pros and cons of using X directly for distributed communication, especially in the short term? Can GAIA be used for interactions (e.g. drag&drop, clipboard, primary, and secondary transfer) for which X is now used? If so, how can interoperability best be maintained with future legacy applications that are not GAIA-compliant? Can GAIA be implemented so that the choice of storage and transport layer can be hidden and replaced, with interoperability negotiated across gateways? What is the relationship between the use of CORBA and next generation OO toolkit technology (e.g. FRESCO)? To what degree does multicast messaging need to be provided or accommodated by GAIA? Where and how must security be addressed in GAIA? To what extent does the need to support multimedia affect GAIA and the infrastructure on which it is built?
Window System Interoperability ==============================
How can GAIA be implemented so it is available in multiple windowing environments? How can GAIA be integrated with other interchange and interoperability frameworks, when both are available on the same machine, or when they interoperate across a network? In an environment in which another interchange and interoperability framework is dominant, can GAIA interfaces act as a layered API on top of them? In an environment in which GAIA is dominant, are special hooks needed to allow other interchange and interoperability frameworks to act as a layered API on top of GAIA? Within mixed window systems, how can windows from one system be embedded in the other system's window? GAIA Services and Interfaces ============================
What services are needed (for example, Format Conversion, Service Registration and Location, Interchange, Printing, Embedding, Dynamic Updating, Linking, Floor Control, Script Recording, etc.)? What role does e-mail support play in GAIA? Which services can be provided in separate server processes? Which services be distributed? Which services can be replicated, and how can they be managed? When multiple services satisfy a need, how can the best service be found, and how scalable is the approach?
Format Negotiation & Conversion ------------------------------- How does a information requester describe the information it is requesting (e.g. what portion of the source's state, what it wants to know about that portion, in what encoding it wants to receive the information)? How does an information supplier describe the information it can provide? How do information suppliers and requesters describe the lossiness and accuracy of the information provided or requested? How can format negotiation best support compound encodings? (i.e. with subparts representing separate portions of information, each potentially in its own encoding)? How is the best encoding be determined which matches what a supplier can provide and what a requester wants? How are convertors supported, and under what circumstances are they used? What additional attributes are used to choose convertors (e.g. latency limitations and usage fees)? Can chains of convertors be used, and if so, how is the search for a suitable chain constrained? Should GAIA provide special support to deal with interchange of tagged data where the meaning of the tags are separately defined? Dynamic Updating ---------------- What communication mechanism should be used for delivering updates? How should alternative formats for providing incremental and non-incremental updates be specified? What kinds of mechanisms might be used to support conversion between incremental suppliers and non-incremental consumers, and vice versa? Should bidirectional updating be explicitly supported (beyond separate one way connections), and if so, what mechanisms are available for synchronization or direction control? Can convertors be used to convert dynamic update formats? When a source or destination client is unavailable, should caching be provided, and if so, as the only delayed updating mechanism? If caching is provided, should it be at the source, at the destination, or elsewhere? How should incremental updates be cached? Live Embedding -------------- How do the embedded application and the parent application negotiate the size of the client window -- both initially, and possibly when the embedded applications gains or loses focus? How does keyboard focus (particularly in the case of keyboard navigation) get transferred from the embedded to the parent application and vice versa? How does the embedded application provide a menu to be added to the parent application's menubar? When printing compound documents, how are the rendering formats of embedded data negotiated? In what other ways do the parent and the embedded client need to negotiate? Linking ------- Should the destination of a link be hardcoded directly into the source, or indirectly through a link service? Should links to regions of objects be supported, and if so, how? How are regions updated, and what happens when they change? Are reference links (used to refer to another document or document region which is meant to be embedded or viewed separately), traversal links (used, for hypertext, etc.), and data links (which provide dynamically updated data to be included at the link site) all supported? Are reference links, traversal links, and data links interconvertible, and if so, how? What information about a link needs to be communicated between the source and destination, and how is it communicated? Can the availability of linking information be dependent upon context, and if so, how is it controlled? What interaction between links and version management need to be considered or supported? To what degree should link services support interpretation of SGML Hytime links? Groupware --------- Are GAIA's dynamic update and data linking services an appropriate base for building groupware applications? If not, what should be used instead? What additional services are required (e.g. view coordination, floor control, synchronization, voting, feedback management, consistency management, merge control, etc.)? How can overlaid annotations best be supported? What interaction between groupware services and transactions need to be considered or supported? What consideration needs to be given to support of groupware in situations where interactions have high latency? Multi-Application Scripting --------------------------- What language or language architecture should be used for scripts that can simultaneously interact with multiple applications? Does the language architecture support nested scripts that can be passed to an application's specialized script interpreter? Is there a need for a standard script interpreter that can be linked with an application? What mechanism is used for automatically recording scripts? Are there different mechanisms or architectures for recording (and playing back) semantic actions vs. for user gestures? How does the architecture handle playback of user gestures when the geometry or the view of the application has changed? To what degree can or should a scripting architecture act as a base on top of which other GAIA functionality can be implemented? How can the security concerns of trojan horse scripts can addressed?
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