GATE IT 2005 | Question: 66

Question

In a data flow diagram, the segment shown below is identified as having transaction flow characteristics, with $p_2$ identified as the transaction center

A first level architectural design of this segment will result in a set of process modules with an associated invocation sequence. The most appropriate architecture is

• A. $p_1$ invokes $p_2, p_2$ invokes either $p_3,$ or $p_4,$ or $p_5$
• B. $p_2$ invokes $p_1,$ and then invokes $p_3,$ or $p_4,$ or $p_5$

• C. A new module $T_c$ is defined to control the transaction flow. This module $T_c$ first invokes $p_1$ and then invokes $p_2.$ $p_2$ in turn invokes $p_3,$ or $p_4,$ or $p_5$

• D. A new module $T_c$ is defined to control the transaction flow. This module $T_c$ invokes $p_2.$ $p_2$ invokes $p_1,$ and then invokes $p_3,$ or $p_4,$ or $p_5$

Comments

which concept of transaction is using here?

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@Bikram

sir please help confused between a and c

And do these questions are still in gate syllabus?

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why a new module is defined here to control the transaction needed??

why not A??

Answer 1

Answer: C

A new module T_c is defined to invoke p1 as p1 isn't being invoked in the diagram. Later, p1 invokes p2 which then invokes p3, p4 or p5.

Comments

If p1 can't alone invoke p2, why is there an arrow from p1 to p2? Option C says that Tc invokes p1 and then p2. Then the arrow from p1 to p2 is redundant. If Option C were "A new module Tc is defined to control the transaction flow. This module Tc first invokes pl. p1 then invokes p2. p2 in turn invokes p3, or p4, or p5", then its description would match the flow diagram and would be correct. As of now, I think option A is the stronger answer.

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This is from Software Engineering and no longer needed for GATE -- but required for NET, ISRO etc.

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`@Arjun sir under which module of software engineering does this topic comes in ???

Answer 2

Answer (A) p1 invokes p2, p2 invokes either p3, or p4, or p5.

Answer is not C because C says A new module Tc is defined to control the transaction flow. This module Tc first invokes p1 and then invokes p2.But we can clearly see in the flow diagram p2 is clearly getting invoked by p1 and not by Tc.