Implementation and Support

1. Implementation and Support - Construction, Conversion and Maintenance of the New System

2. What is Systems Implementation? • Systems implementation is the construction of the new system and the delivery of that system into production (meaning day-to-day operation).

3. The Construction Phase of Systems Implementation • Thepurpose of the construction phase is twofold: • To build and test a functional system that fulfills business and design requirements, and • To implement the interfaces between the new system and existing production systems.

4. Build and Test Networks • The purpose of this activity is to build and test new networks and modify existing networks for use by the new system. • The key input is the network design requirements defined during systems design.

5. Build and Test Databases • The purpose of this activity is to build and test new databases and modify existing databases for use by the new system.

6. Install and Test New Software Package • The purpose of this activity is to install any new software packages and make them available in the software library. • The applications programmer will complete the installation and testing of the package according to integration requirements and program documentation that was developed during system design.

7. Write and Test New Programs • The purpose of this activity is to write and test all programs to be developed in-house. • If modules are coded top-down, they should be tested and debugged top-down and as they are written.

8. Testing a New Program • There are three levels of testing to be performed: stub testing, unit or program testing, and systems testing. • Stub testing is the test performed on individual modules, whether they be main program, subroutine, subprogram, block, or paragraph. • Unit or program testing is a test whereby all the modules that have been coded and stub tested are tested as an integrated unit. • Systems testing is a test that ensures that application programs written in isolation work properly when they are integrated into the total system.

9. The Delivery Phase • Conduct a system test to ensure that the new system works properly. • Install databases to be used by the new system. • Provide training and documentation for individuals that will be using the new system. • Prepare a conversion plan to provide a smooth transition to the new system. • Convert from the old system to the new system and evaluate the project and final system.

10. Conduct System Test • The purpose of this activity is to test all software packages, custom-build programs, and any existing programs that comprise the new system to ensure that they all work together.

11. Install Databases • The purpose of this activity is to populate the new systems databases with existing data from the old system.

12. Train System Users • Provide training and documentation to system users to prepare them for a smooth transition to the new system.

13. Conversion • Prepare a detailed conversion plan to provide a smooth transition from the old system to the new system. • Convert to the new system from the old system and evaluate the project experience and final system.

14. Common conversion strategies • Plunge (Direct Changeover) • Parallel conversion • Phased (Gradual) conversion • Pilot (Modular prototype) conversion –typically in a single location

15. What is Systems Support? • Systems support is the on-going maintenance of a system(s) after it has been placed into operation. This includes program maintenance and system improvements. • Systems support often requires developers to revisit activities typically performed in systems analysis, design, and implementation.

16. Systems Maintenance - Correcting Errors • Regardless of how well designed, constructed, and tested a system or application may be, errors or bugs will inevitably occur. • The correcting of bugs is called system maintenance, or program maintenance.

17. System Recovery - Overcoming the “Crash” • A system failure is inevitable. • It generally results in an aborted or ``hung'' program (also called an ``ABEND'' or ``crash'') and possible loss of data. • The systems analyst often fixes the system or acts as intermediary between the users and those who can fix the system.

18. Database Backup and Recovery • Data in a database may be lost or corrupt by invalid or partial update due to the crash. • Backup/Recovery Techniques • Roll back: logging (taking a backup copy) of before-image (image of DB before the transaction), and “rollback” the image when data are lost. • Roll forward: perform transaction on the image (master is intact), upon successful transaction, dump the image onto the master (roll forward).

19. End-User Assistance • No matter how well users have been trained or how well documentation has been written, users will require additional assistance. • The systems analyst is generally on call to assist users with the day-to-day use of specific applications.

20. Systems Enhancement and Reengineering • Adapting an existing system to new requirements is an expectation for all newly implemented systems. • Adaptive maintenance forces an analyst to analyze the new requirement and return to the appropriate phases of systems analysis, design, and implementation.

21. The Year 2000 and Systems Support • The year 2000 problem was the potential of triggering widespread computer application disasters across many corporations.