transaction processing Transaction processing is information processing in computer science that is divided into individual, indivisible operations called ''transactions''. Each transaction must succeed or fail as a complete unit; it can never be only partially compl ...

, a pseudoconversational transaction is a type of transaction that emulates a true conversation in an

interactive Across the many fields concerned with interactivity, including information science, computer science, human-computer interaction, communication, and industrial design, there is little agreement over the meaning of the term "interactivity", but m ...

session. To the end user, it appears as though the program has simply "paused" to request further input, whereas in reality, most resources are released while the input is waiting to be received.

Transparent termination and restart

The controlling program has deliberately saved most of its state during the delay, terminated, and then, on being restarted through new input, restores its previous state. A single

control variable A control variable (or scientific constant) in scientific experimentation is an experimental element which is constant (controlled) and unchanged throughout the course of the investigation. Control variables could strongly influence experimenta ...

is usually retained to hold the current state in terms of the stage of input reached (and therefore what must be recovered at any stage in order to resume processing). The state, including the control variable, is usually preserved in a 'temporary storage record' that maps the variables needing restoration as an aggregate set, usually contained in a single structure (other variables will be re-initialized on restart).

Conserving resources

This method of programming frees up pooled resources (such as

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered ...

) for an indeterminate time. This delay is the end-user 'thinking time' (or response time) and depends on human factors including speed of typing. For systems supporting many thousands of users on a single processor, it allows the transparent 'look and feel' of a true conversational session without tying up limited resources.

References

External links

Pseudoconversational and conversational design
by IBM * {{software-stub