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Question on legacy system

Ramesh Kannan
Greenhorn

Joined: Mar 19, 2007
Posts: 9
A telecommunications company, xyx, is building an enterprise system to allow the xyx co. support staff to access customer information over an intranet. All of the customer information is stored in a legacy system and can only be accessed using a VT100 terminal session. You must create an architecture to access the legacy system.
What should you use to encapsulate access to the legacy system?
A. A JDBC connection that uses SQL to query the legacy system.
B. AN EJB entity bean that uses JMS to interact with the legacy system.
C. A distributed CORBA object that uses IIOP to interact with the legacy system.
D. An EJB session bean that uses a screen-scraping tool to interact with the legacy system.

Guys, let me know the correct answer.
Rahul Bhattacharjee
Ranch Hand

Joined: Nov 29, 2005
Posts: 2308
Legacy systems usually have defined access points for communication with external systems.You need to know that to design a system that will communicate with it.


Rahul Bhattacharjee
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Frank Kuepper
Ranch Hand

Joined: Mar 16, 2007
Posts: 45
The only thing we get to know about the legacy system is, that it can ONLY be accessed via VT100 terminals. So Rahul's assumption is a bit optimistic ;-)

Given the facts in the question the only option is D.

A. is wrong, because we don't know what database the legacy system is running on - so SQL might be inapplicable.
B. and C. are wrong as we don't know, if the legacy system supports any communication.

Thus leaving D. the only choice: building a screen scraper to interact with the legacy's system VT100-interface.


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Rahul Bhattacharjee
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Joined: Nov 29, 2005
Posts: 2308
Legacy System from wikipedia:

A legacy system is an existing computer system or application program which continues to be used because the user (typically an organization) does not want to replace or redesign it.


I do not see any reason why is cannot have an interface through external systems can communicate with it.Accessing the database is possible by direct access should not be allowed , it should only be accessed by the legacy system.

If you try to bypass the legacy system and directly access the database , then you are making a whole new application based on previous user data.
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 41532
    
  53
Originally posted by Rahul Bhattacharjee:
I do not see any reason why is cannot have an interface through external systems can communicate with it. Accessing the database is possible


The question clearly states that it can only be accessed through a terminal session. That rules out databases and other ways of accessing it.


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