tfrancis@wpi.wpi.edu (Krishan M Nainani) (08/11/89)
Hi Folks, Recently, I discovered the following article in C.L.I which interested me since this was the type of research that was done a few years ago in the research lab that I am currently involved with. For those of you who missed it, here it is: From: davis@COMMUNITY-CHEST.MITRE.ORG (dave davis) Subject: Handling objects in a distributed system --------------------------start of article------------------------------- Ed Berard poses an issue in dealing with objects in a distributed system: how to send an object to another node. As Ed suggests, one solution is to have the knowledge of all the objects within the system be present at each node. However, this might be inefficient in certain cases, and could cause difficulties if we with to create new objects dynamically. I suggest that an approach would be to transmit "installation instructions" (or template, or frame) with each transmitted object so that the recieving node only needs to know a general schema for object installation. The instructions would have to contain information about the object's interface, its last state, and enough information about its structure to recreate it locally. Assuming for a moment that all of the objects in our system are created from more primitive objects the mechanism need only have a representative of each primitive object on hand, and know how to apply them in a specific case. Such a mechanism could also be two-way, translating objects to/from non-objective representations. This mechanism might also be of use in storing and retrieving persistent objects off-line. ================================================================= Dave Davis MITRE Corp; McLean, VA ------------------end of article-------------------------------------- My comments: Dave, your idea was implemented here using a DDL (Data Description Language) which essentially passed the "type" of the object that you wanted to pass. Obviously, the object itself was passed but the DDL was used to interpret the object. In fact, even lists (also lists of lists of ...) could be implemented. To my understanding there were a few papers published on this but I am not sure in which journal they were published. In addition to this, this software took care of sending messages even in a Heterogenous Processor Environment. As a result, it is a really valuable tool for my current work. Krishan Nainani (reply-to :tfrancis@wpi.wpi.edu)