web access to mainframes

Copyright Bridgewater Consultants, Inc. 19991

Web access to Mainframes

• This presentation will explain the pros and cons of the common options that exist for providing Web access to mainframe systems.

• It will also describe how BW*Wizard can significantly reduce development times for industrial strength GUI applications in CICS DB2 environments.


Agenda

• About Bridgewater

• Current Situation

• The Challenge

• The Considerations

• The Options

• Recommendation

• About BW*Wizard


About Bridgewater

• We are a five year old San Diego based software development and professional services firm that serves the large systems market.

• Our focus is on helping clients significantly increase developer productivity by automating the routine aspects of database access development in COBOL, Java, and other languages.

• Our flagship product is BW*Wizard a template driven, pure source code generator.


Current Mainframe Structure

COBOLApplication

CICS

3270 Terminal

Database

Legacy System


Mainframe Attributes

• What makes mainframes attractive?– Reliability…it’s there when you need it– Scalability…you can predictably add capacity– Security…data integrity is high– Maintainability…resources are available

• The above elements are critical to most organizations and important factors to consider when designing GUI access.


Desired Situation

LegacyMainframe

System

Browser

3270 Terminal


The Issues

LegacyMainframe

System

Browser

3270 Terminal

PersistentConnection

StatelessConnection

TextBased

GUIBased


The Issues• Persistent Connections versus Stateless

– Mainframe sessions are tightly controlled and secure through a persistent connection made up of related transactions

– Web connections are only made when initiated and each interaction is unrelated to other interactions

– Dealing with this connection issue correctly is essential to maintaining session and corresponding data integrity


The Issues

• TUI versus GUI– 3270 terminals are character oriented only and

the data streams from the host contain specific screen formatting commands

– Different Web browsers may format an HTML data stream in a variety of different ways

– Those differences in presentation methodology can produce many data entry and display challenges


The Challenge

• Providing users with the appropriate industrial strength browser access in a legacy environment while continuing to meet the IT needs of the organization in matters relating to security, reliability, scalability, flexibility, and maintainability.


The Check List

• System Factors– Session Integrity– Data Integrity– Responsiveness– Scalability– Flexibility– Maintenance Requirements


The Check List

• User Factors– Which users and applications require GUI?– Is terminal emulation or enhanced GUI

capability preferred for the browser access? – Which users and applications will require

continued green screen support?


The Options

• Three primary ways of providing browser access– Interactive Terminal Access– Direct Database Access– CICS Program to Program Communications


Interactive Terminal Access

LegacyMainframe

System

Browser

3270 Terminal

WebServer

HTML

3270 Data Stream

3270 DataStream



• Commonly known as “screen scraping” due to terminal emulation characteristic

• Two main methods with varying degrees of translation being performed at the server– Browser Based Terminal Viewers and Browser

Based Terminal Emulators receive a 3270 data stream and convert it into HTML

– On the fly HTML translation occurs at the server and requires only a Browser to view



• Pros and Cons

– Straight terminal emulation can be implemented quickly

– Storing terminal emulators on a server reduces maintenance

– Terminal emulation functionality may be limited

– Session integrity may be difficult to ensure

– Taking full advantage of Java’s capabilities to graphically display 3270 screens may be extremely time consuming and costly


Direct Database Access

Browser WebServer

DatabaseGateway

NewApplication

DB2



• Involves rewriting the system from the database out to the screen– Could be used when no existing code will do

the job – Development is typically done in Java– Extensive database development must be done

in this scenario



• Pros and Cons

– Starting from scratch provides an opportunity to precisely define the program structure

– GUI front end should be outstanding in terms of quality

– 3270 access is not available?

– Qualified development resources may be difficult to come by

– Transaction management capabilities may be unproven and data integrity may be an issue


CICS Program to Program Communications

3270Terminal

JavaBrowser Java/CICS

Gateway

COBOL/CICS/DB2Legacy System

WebServer

*ECI

*External Call Interface



• Capitalizes on the best elements of a legacy system while providing a full GUI front end– Presentation logic and business logic are

segmented using this approach

– COBOL is used for business logic and 3270 screens

– Java is used for GUI screens

– CICS is used to manage transactions to ensure session and data integrity



• Pros and Cons

– Robust architecture provides flexibility, scalability, security, and maintainability

– Sophisticated GUI applications can access multimedia and the same data that 3270 terminals are accessing which provides a great deal of flexibility

– New database access applications must be developed in Java and/or COBOL

– Business logic may also have to be reworked


Recommendations

• Interactive Terminal Access

– Could work well in simple terminal emulation applications

• Direct Database Access

– Well suited to developing entirely new graphics oriented applications

• CICS Program to Program Communications

– Ideal for hybrid 3270/GUI environments requiring all of the strengths of a legacy environment


Program to Program Development Challenge

• Monolithic Code is the problem

– An entire system rewrite is not a practical avenue for most organizations to pursue

– Gradually introducing Browser access on a project basis can provide an organization with a good feel for the technology and its capabilities

– A tool like BW*Wizard can quickly produce fully functioning Java and COBOL database access programs providing all of the benefits of Java and the legacy system


What is BW*Wizard?

• It is a Windows based database access application development tool that rapidly produces complete new TUI and GUI front ends on systems using COBOL CICS and DB2.– COBOL support is provided for Mainframe, VisualAge

COBOL, Micro Focus, and others.

– Java support is provided for most popular types including Microsoft J++, Symantec Visual Café, VisualAge Java, and others.


Database Access Development

DatabaseAccess

Navigation BusinessLogic

PresentationError

Handling


Database Access Programming Requirements

• Database Access (required)– Routine and efficient storage and retrieval of data to

ensure data integrity and database performance

• Error handling (required)– Consistent feedback to users regarding data entry to

create environment for valid and efficiently performed entries


Database Access Programming Requirements

• Presentation (required)– Consistent look and feel can decrease training costs and

increase users’ effectiveness

• Navigation (required)– Consistent methodology for moving between screens

can increase user productivity

• Business Logic (may be required)– Unique code, based on corporate standards, to meet

business requirements


Manual Database Access Development Methodology

• New database access programs are created on an as required basis.– New screens are not usually developed from scratch…

they are usually the result of copying and editing existing programs

– Tables, fields, calculated fields, and business logic are stripped from an existing program leaving the basic structure of the program

– All of the specific aspects of the program are then hand coded to meet business needs


Manual Code Reuse

• Primary Advantage– Capitalizes on existing code to save time when

developing new applications

• Primary Disadvantages– Significant amounts of time spent rewriting code that

does not directly support new business logic

– Developer productivity is not optimized and user interfaces may be inconsistent

– Corporate coding standards may not be applied


The Power of Automated Design Reuse

• BW*Wizard produces error free programs in minutes that would take days to hand code by automating all of the routine aspects of design reuse saving time and effort– Navigation, error handling, presentation, and database

access are all handled consistently according to corporate standards

– Code is easier to maintain

– Pure source code is produced providing maximum flexibility in terms of maintenance and appearance


BW*Wizard Template Design

• BW*Wizard Templates meet the needs of the three main presentation requirements– Menu

– List

– ISUD (Insert, Select, Update, Delete)

• BW*Wizard also builds the complete I/O, error handling, and navigation code to complete the program

• Any required business logic can then be added


How does BW*Wizard Work?

BW*Wizard GUI&

Application Engine

BW*WizardRepository

(Labels, Edits)

BW*WizardCode Templates

YourDDL

ProjectDefinition

Built TUI or GUI Application


What Our Customers Say

“BW*Wizard’s pre-tested code templates provide us with a strong foundation for the development of new applications. It then goes on to build those applications at blazing speeds saving us time and money.”

John J. Spiewak TVSM Inc.



“Our initial investment in BW*Wizard has been repaid many times over through significantly increased productivity. It enables our developers to quickly produce error-free programs that meet our corporate standards which reduces our maintenance expenses.”

Perry Bredeson

Musicland Stores Corp.



“The productivity boost from this product is incredible. You can literally create a working screen in just five minutes. However, the most impressive fact is that every application has been error free from the first build.”

Tom Bishop USDA


Next Steps

• One hour demo at your location– BW*Wizard will build a new 3270 screen and a Java GUI both accessing the same server in

10 minutes– All of the required SQL, navigation, error handling and presentation code will be generated by

BW*Wizard

• You will get a full appreciation for the power and productivity increase that BW*Wizard can bring to your organization’s development efforts in both TUI and GUI environments.

web access to mainframes

Documents

gui access

web access

terminal emulators

server browser

terminal viewers

terminal web server

direct database access

gui screens cics