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VOSS-on-server or VOSS-on-client?
Q: “What are the pros and cons of configuring VOSS-on-server or VOSS-on-client?”
A: VOSS-on-client is conceptually simpler since the user interface and virtual objects can both be accessed directly by the application running on the client, but in this configuration all objects touched in a transaction travel over the network to the client. This configuration can be multi-user since any number of images on separate machines on a LAN can connect to the same virtual space(s) on file-server(s). However, it’s more vulnerable to crashes, as a desktop machine could be switched off in the middle of committing a transaction, which will block all access to the virtual spaces touched by that transaction until after a Database Administration person has performed a restart and backup (if the transaction was writing to the transaction log at that instant), or a rollforward recovery (if it was writing to (one of) the work virtual space(s) at that instant).
When a VOSS-enabled image is running on a server, the application serves remote clients by concurrent background processes in the image. This keeps the entire transaction on the server, but means the application must communicate with its clients via byte string data transfer. Virtual objects may be serialized for transmission and re-instantiation between client and server if the client is also running Smalltalk, but synchronization is the responsibility of the application.
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