Graphical User Front-End

Overview

Symptoms

Organizations with an immediate need to bring a client/server "look and feel" to end users typically begin by adding a graphical user interface (GUI) front-end to one or more systems. This is a scenario that impacts core systems to the degree desired, while providing a graphical user interface to end users. Symptoms are listed below:

· Users require an improved interface to legacy system

· Input can be streamlined through more efficient data gathering and data transfer to host

· Core system functionality, data structures and data interfaces remain unchanged

· I/O and business logic isolation can be, minimized or applied on an extended basis to move validation or other logic to workstation environments on a selective basis

· Front-end edits may be moved to client workstation

Requirements

The basic requirement of this scenario is to deliver information to end users under a graphical front-end to access operational data using state-of-the-art interface technology . The focus is on providing GUI interface that feeds transactions to core host systems while streamlining user interface. Cross system integration is not supported under this scenario. Requirements for this scenario are listed below:

· Redesign information presentation without impacting core systems

· Provide a graphical, front-end to send and receive data to and from host system

· Consolidate, where possible, multiple input/output screens into fewer GUI interfaces

· Batch and feed multiple textual transactions to host

· Replace host I/O macros while leaving I/O access logic intact

· Move edit criteria, or other business logic as applicable, to the workstation environment

· Leave host data structures and data access routines intact

· Add, where applicable, GUI output screens to replace selected batch output reporting capabilities

· Implement client to host interface software to support transaction input/output linkages (i.e. CICS or IMS transaction unload and download)

· Remodularize certain edit logic from host where appropriate

Graphical User Front-End Planning Considerations

Comsys-TIM views the development of a graphical front-end a host based system as an interim step to provide users with more streamlined access to legacy data. If multi-system integration, core system redesign, data access redesign or functional/data distribution is required, this scenario is either an interim step or may not apply.

Additional issues to consider when undertaking this approach include:

· Verification that GUI front-end is primary user requirement

· Utilization of middleware enabling task to "fool" host into thinking it is still receiving host based transaction

· Review of selected middleware and GUI technology for applicability to environment and to each other

· Incorporation of Infrastructure Stabilization scenario as a way to concurrently or selectively improve and stabilize core system

· Based on need to rehost edit or business logic to the workstation, incorporation of re-aggregation task to remodularize I/O, validation or actual business logic

· Remodularization of edit/validation logic that could be downloaded to client environment

· Ability to link edit/validation logic to GUI front-end based on technology being used

· Determination of long-term view of how this approach will mesh with further core system redesign

Build Graphical User Interface Plan

Develop Assessment Proposal

Objective setting/proposal development

Note: Objectives should not include changing baseline systems - this is an indication to research another scenario. Only one hypothesis is envisioned here involving a GUI front-end on multiple systems.

Develop Inventory Analysis Objectives

Establish Assessment Task List

Note: Refer to the remaining assessment steps in assessment section below.

Finalize Environmental Analysis Work Plan

Note: Limit process flow analysis to high-level, automated (where available) scanning of key source modules. Intent is to identify code quality as input to slicing of selected edit logic if this is objective.

Finalize Process Flow Analysis Work Estimates

Note: Data definition analysis is limited to system-wide I/O record analysis - bypass all other steps with exception of recording I/O record count related metrics.

Finalize Data Definition Analysis Work Estimates

Note: This analysis will focus on capturing on-line user views and, optionally, batch reporting views of various systems' data.

Finalize Presentation Layer Analysis Plans

Note: User backlog analysis is limited to identifying specific requests linked to integration and presentation requirements.

Finalize User Backlog Analysis Plan

Note: Interim and strategic redevelopment plans are highly modified hybrids - see suggested tasks identified in the remainder of this scenario.

Finalize Interim Planning Task Effort

Finalize Strategic Redevelopment Work Effort

Develop Inventory Analysis Work Plan

Complete Inventory Analysis Assessment Proposal

Perform Baseline Analysis

Environmental analysis

Note: The following steps are performed for each system input to this assessment.

Identify & Categorize Physical System Components

Inventory & Cross Reference Mainframe Components

Review & Refine Environmental Analysis Results

Note: Concentrate on missing components that could cause later analysis problems with on-line screens or database definitions.

Produce Environmental Counts and Scores

Inventory & Cross Reference Mainframe Components

Data definition analysis

Note: The following steps are performed for each system input to this assessment. Limit efforts to I/O record related information based on need to verify screen related work areas for input to front-end development.

Perform System-Wide Data Definition Analysis

Assign Data Definition Metric Counts

Presentation layer assessment

Note: The following steps are performed for each system input to this assessment. Note nature and type of user views as key input to front-end planning.

Identify Batch Output Presentation Media

Identify & Categorize Batch Input Sources

Identify & Categorize On-Line Presentation Media

Summarize User Supported Environments

Record Presentation Layer Analysis Metrics

Data access layer assessment

Note: The following steps are performed for each system input to this assessment.

Finalize Database & Data File Inventory

Assess Physical Data Usage Redundancy

Determine Data Integration Levels

Rate Data Architecture Conformance

Summarize Data Architecture Analysis

User backlog requirements analysis

Note: Focus on identifying specific presentation and integration requirements.

Build Graphical User Front-End Plan

Create system stabilization plan

Create Interim Plan Outline

Correlate Analysis Requirements & Findings

Identify Positioning Tasks & Cost Analysis

Note: Only Positioning task will be data name rationalization.

Finalize Interim Support Work Plan

Note: Application staging estimates must be developed for each subsequent Positioning step. If these steps are not applied, bypass application staging.

Finalize Application Staging Plan

Note: Based on requirement to selectively slice edit logic from edit/update programs, determine limited applicability of the following three steps. Again, if no edit logic is being transferred from host to client, bypass these steps.

Finalize Flaw Analysis & Removal Work Plan

Determine Restructuring Work Effort

Identify Support Structure Adjustments

Integrate Interim Plan & Strategic Objectives

Create middleware/user interface development plan

Note: This plan is limited to a few steps as identified below.

Build Strategic Redevelopment Plan

Note: The following steps identify work tasks and associated estimates required to complete integrated front-end planning.

Finalize Presentation Analysis Work Plan

Note: Middleware steps are distributed across two different activities under the last phase of this scenario. Estimate accordingly.

Estimate Middleware Enabling Work Effort

Note: Edit logic slicing is performed based on middleware setup and implementation effort. Analysts must know which routines require validation logic download prior to performing edit logic deactivation and transfer.

Finalize Code Slicing Work Plant

Note: The following step is a Positioning step.

Finalize Redevelopment Work Plan

Modify Application System Baseline

Stabilize Legacy Baseline

Note: Perform this series of steps only on programs where edit/validation logic is to be sliced out of the program and moved to client environment.

Application staging

Identify & Categorize Components of Interest

Create Working Version Libraries

Document Versions and Library Protocol

Synchronize Staged Source with Production

Flaw analysis & removal

Produce Detailed Flaw Analysis Reports

Note: Enter and execute following steps only as required.

Eliminate Runaway Logic Paths

Assess and Eliminate Dead Code

Review & Eliminate Active Exits

Review & Eliminate Looping Range Violations

Review & Eliminate Recursive Performs

Review & Eliminate ALTER Logic

Perform Quality Review and Finalize Changes

Code restructuring

Create Detail Restructuring Analysis

Perform Program Structuring Adjustments

Establish Restructuring Parameters

Perform Source Code Restructuring

Validation

Perform Code Quality Assurance

Compile & Link Baseline Components

Compile & Link Positioned Components

Identify Validation Data Sets

Refine Validation Data Sets

Validate Modified Programs

Obtain Validation Sign-Off

Develop Integrated Graphical Front-End

Finalize Client/Server Design

Client server design requirements finalization

Note: The following steps are taken from middleware enabling and deal with specific configurations within a client/server environment. Use as a check list for environmental design.

Finalize Middleware Tool Requirements

Design Client Server Interfaces

Complete User Interface & Validation Design

Presentation analysis

Note: Perform the following step for each screen and related program being front-ended. Note that automated import tools are available in certain cases.

Categorize Existing Screen & Report Layouts

Perform Presentation Functional Analysis

Determine Reusability Under Target System

Note: Import target normally has graphical screen design facilities that may be used to further customize user GUI views.

Refine Target System Report & Screen Design

Edit & validation logic remodularization

Note: Once screen design is completed, selected edit logic may be ported from host to client environment. The key issue is establishing a GUI call to access a sub-routine that can receive and validate input data.

Develop Program Slicing Analysis

Perform Program Slicing Process

Note: The following involves creating an executable sub-routine for the workstation environment that can be called from a GUI interface. If alternative approaches are available, they may be explored. Host based programs must still remain as executable units.

Re-Configure Slice Related Components

Finalize Interactive Communication Links

Middleware communication finalization

Generate Middleware Communication Code

Note: Data migration under the integration scenario emphasizes reconciliation and consolidation of redundant or overlapping physical data for query purposes only.

Enable Middleware Mainframe Linkage

Finalize and Link Middleware Applications

Note: The following step is optional. If the organization wants to access other data stores directly (on host or another server) while bypassing host programs, this step may be used. Direct linkages are possible using some of the same middleware tools applied earlier in this scenario. Refer to step below and related tool guidelines.

Build Middleware Direct Data Store Links