Siemens U3585-J-Z125-8-76 1 manual Performance expectations of the user, Interactive mode criteria

SM2 monitoring program Performance expectations of the user

2.11 Performance expectations of the user

When assessing the performance of a DP system, the user is generally interested in:

●the time it takes for the system to respond to requests,

●how many requests the system can handle within a given period of time, and

●what resources are used.

The performance level of the hardware (e.g. the number of instructions processed per second) and of the operating system (e.g. task management efficiency) are generally of secondary interest.

Interactive mode criteria

A distinction is made between inquiry-and-transaction mode and timesharing mode:

In inquiry-and-transaction mode, the terminal users can communicate only with programs which are specific to a given application. Normally, a large number of users interact with a relatively small number of application programs.

In interactive (or timesharing) mode, the terminal users enter their own application programs for interactively processing a given task. The application programs are generally controlled by system programs for creating, testing and updating files and programs.

In both inquiry-and-transaction mode and timesharing mode, the unit of DP operation is a transaction.

The transaction time is the delay between the arrival of the input at the host and the output of the acknowledgment. The DP system can output several responses with different response times for a single transaction. If resources are not released when a transaction is completed but are reserved for the next transaction, the transaction is known as a multi-step transaction.

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