Hardware and software requirements
DBAccess Server V9.1 can be used on any server supported by BS2000/OSD-BC V9.0 or higher.
The software products currently required are listed in the release notes.
Architecture of the DBAccess Server
The DBAccess Server is usually started with /START-SESDBA-SERVER in a batch task. This task is called an admin task below. The admin task starts a further task called a main task.
The main task creates further tasks called server tasks. There are two types of server tasks:
Free server tasks are tasks that have been started and initialized but have not yet established a connection.
Active server tasks are tasks that have already established a connection.
Admin task
Admin tasks receive administration requests (e.g. to terminate the server) that are also processed within this task.
Main task
After it is started, the main task creates a number of server tasks corresponding to the number of free tasks to be reserved (setting in the initialization file, see section "Initialization file (start parameters)").
Connect requests from the clients for SESAM/SQL sessions are sent to the main task. The main task forwards these connect requests to a free server task.
A new server task is then started if the total number of free and active tasks is smaller than the maximum number of tasks (setting in the in the initialization file, see section "Initialization file (start parameters)").
Server task
A server task is responsible for communication with the requesting user (client). SESAM/SQL requests are forwarded to the database system and processed within this task.
Architecture of SESAM-DBAccess