20. Distributed Systems Support

<Applications are normally decomposed (i.e., split) into individual blocks where each block handles specific aspects of the application.
These individual blocks then cooperate with each other by means of interprocess communication (IPC) using objects like semaphores, mailboxes, mutexes, regions, shared memory etc.
While the performance of one node may be sufficient for moderately complex applications making up a system, there are many applications that need to be distributed across several nodes and/or hosts. Considerations for decomposing an application are discussed in chapter “Designing for Scalability” of this training.
 
INtime provides support for distributed systems by two layers. For an introduction see chapter “INtime Architecture”, slides “Scaling the System – DSM and Global Objects Technology” of this training.
  • Distributed System Management (DSM) – monitors “health” of all nodes and handles dependencies between processes on any node of the system
  • Global Objects (GOBS) Technology – split into GOBSmgr and GOBSnet.
  • GOBSmgr: facilitates access to objects on other nodes (then named global objects) by means of a reference objects.
  • GOBSnet: if the global object resides on a node in another host, GOBSmgr transparently uses GOBSnet to access it.TODO>: Insert description text here... And don't forget to add keyword for this topic