Maintaining software solutions

Maintaining software solutions Maintenance is an ongoing process. Includes correction of errors and upgrades to enhance the functionality. Comprises: A) Identifying and determining what changes should be made. B) Ongoing communication with users. C) Software Development cycle begins. D) Method of distribution devised. E) Modification installed. F) Documentation.

Modification of code to meet changed requirements Reasons to change code: Bug fixes New hardware and new software purchases Upgrades to operating systems Upgrades to make use of additional features Requirements change e.g.. Customised software COTS (customised off-the-shelf) products are particularly susceptible to upgrades

Modification of code to meet changed requirements Patch A patch is an actual piece of executable code that is inserted into (patched into) an existing executable program Script A list of commands that can be executed without user interaction. Macro A symbol, name, or key combination that activates a series of commands, actions, or keystrokes. Many programs allow the creation of macros to automate common tasks

Location of section to be altered Location determined through: A) Structure Charts B) Data Flow Diagrams C) IPO Diagrams D) Actual source code

Determining changes to be made Changes may be required to: A) Source Code B) Data Structures C) Files D) User Interface

Implementing and testing the solution The implementation of modifications can have a ripple effect to other aspects of the application Problems minimised if modular approach implemented. Modules used in several places in program should retain original input/output parameters. Altering parameters will require modifications to each higher-level calling module. Testing should occur using same techniques as deployment of new products i.e. use same test data and CASE tool scripts.

Documenting changes Changes must be tracked and fully documented. Large projects can contain thousands of routines so monitoring and keeping track of changes requires extensive documentation . Configuration Management is the systematic control of changes to a product. Configuration Management CASE tools are available to automate the control and documentation of changes. Source Code Documentation. Updating Associated Hardcopy Documentation and Online Help.

Use of Case tools to monitor changes and versions Computer aided software engineering (CASE ) tools are available to automate the process of maintaining records. Systematic control of changes to a software product is known as configuration management(CM) or software configuration management (SCM). Functions include: A) Change Management: history is maintained of each modification and by whom. B) Parallel Development: Parallel development CASE tools enable multiple users to work on the same project without fear of duplication or destroying another team member’s work. Files are checked out, which effectively locks the file, preventing other’s from making changes. Once modifications are complete, the module is checked in, which releases the file.

Use of Case tools to monitor changes and versions C) Version Control: Version control CASE tools manage multiple versions of software components or module. The system tracks which version of each component or module should be used when the application is finally reassembled. Previous versions of applications can be reconstructed.

Versioning If changes are made, an upgrade from version 1.0 to Version 1.0.1 : Indicates minute change to the program. It may not include any changes to the user interface. Version 1.1 : indicates larger changes to the program, addition of new features or small changes to the interface to make the program easier to use. Version 2.0 : Indicates huge changes to the program. A completely new user interface, or large changes to the features of the program.