Here follows a position paper for the joint W3C/OMG workshop on Distributed Objects and Mobile Code. - ---- BUILDING A WEB FROM DISTRIBUTED OBJECTS ======================================= CORBA-based Web Transport: ANSAweb ================================== ANSAweb is a technology developed by the Information Services Framework at APM, and currently being used experimentally there and elsewhere. ANSAweb provides a minimal set of operations to allow inter-operation between CORBA and WWW information services. It provides to the CORBA world a facility allowing the transport of documents in a manner inter-operable with the Web, and it offers the Web a transport type extensible to performing CORBA method invocations, without any modification of clients or servers being necessary for the simple case of serving HTTP traffic. More information about ANSAweb can be found at <URL:http://www.ansa.co.uk/ANSA/ISF/index_1.html>. End Systems 1: Advanced Web Servers =================================== Current Web servers are quite clumsy; a single large application handles document retrieval, while other services are farmed out to CGI programs. The CGI programs are stateless - any state required must be explicitly stored, usually in a file system or a database. They also suffer from relatively high start-up overhead on most platforms due to the creation of another process and the reading-in of state information. A server built from object components has several advantages over existing servers: 1. It is easily and transparently distributed. If the underlying object system supports migration, then data can move to be near the point of access automatically; similarly, replication can occur in a transparent manner. 2. It is extensible. As new applications arrive, objects to handle them can be added to the implementation as easily as CGI programs may be added to current servers. 3. Object life-cycle management can be implemented, so that frequently-accessed objects remain 'live', while other objects may be passivated to disc between invocations. End Systems 2: Advanced Web Clients =================================== The increasing number of buildings with high-bandwidth connections (as a result of the popularity of cable television) means that the oft-predicted boom in "appliance computing" is now much more likely than it has ever been. Many users have grown up with games consoles; they expect simply to plug in, choose an application (game), and start using it. They do not want to be made aware of the underlying operating system. Future clients will not want to store copies of large applications that are used infrequently - even for those applications that are used frequently, there are large parts which are rarely, if ever, used. For example, a word-processor contains utilities to import documents from many different legacy systems, most of which a given user may never require. If the word-processor supplier didn't provide a converter for your obscure home-grown format, you would like to be able to develop and integrate your own converter. The expected proliferation of plug-and-play components will require effective configuration management. Automatic configuration management is a big area for work and development. Consider, for example, how much work configuration management can be on one of today's PCs, then imagine how much that will expand when software objects are added and removed many times per session. - --- Toby Speight <tms@ansa.co.uk> APM Ltd., Poseidon House, Castle Park, Cambridge CB3 0RD Acknowledgements: Thanks are due to colleagues at APM for many of the ideas mentioned here and much of the implementation of ANSAweb. In particular, Andrew Herbert <ajh@ansa.co.uk>, Mark Madsen <msm@ansa.co.uk>, and Owen Rees <rtor@ansa.co.uk> have all contributed to this paper. - ---- - -- Toby Speight <tms@ansa.co.uk> APM Ltd., Poseidon House, Castle Park, Cambridge CB3 0RD -----BEGIN PGP SIGNATURE----- Version: 2.6.2i Comment: Processed by Mailcrypt 3.4, an Emacs/PGP interface iQB1AwUBMUQZZ+dsuUurvcRtAQH1CAL5AYD3ICbkI/kO6ixhjoZcagPvusu6+m0e q9kL1t+4JEpPnEBek4AQbH+z1aNNebRyhskriHDzbVL1lNvpqatniey9F7qgKkIY DPeiCnQrA1bteHGaUti2tsO8YRUSIP3b =pemL -----END PGP SIGNATURE-----