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IMPLEMENTATION AND MAINTENANCE




After the plan for an information system is approved, it’s time to start building it. The implementation phase can include: purchase and install hardware and/or software, create applications, test applications, finalize documentation, train users, convert data, convert to new system.

Application testing is performed in three ways: unit testing, integration testing, and system testing. Unit testing and integration testing are usually performed in a test area. A test area might to be located in an isolated section of storage on the computer system that runs the organization’s regular information system, or might be located on an entirely separate computer system. When a problem is discovered during unit testing or integration testing, the team must track down the source of the problem and correct it. Unit testing and integration testing are then repeated to make sure the problem is corrected, and no new problems were introduced when the original problem was fixed.

The data for a new information system might exist in card files, file folders, or an old information system. This data must be loaded into the new system - a process called “data conversion”. When converting data from a manual system to a computer system, the data can be typed or scanned electronically into the appropriate storage media. When converting data from an existing computer system to a new system, a programmer typically writes conversion software to read the old data and convert it into a format that is usable by the new system.

System conversion refers to the process of deactivating an old information system and activating a new one. It is also referred to as “cutover” or “go live”. There are several strategies for converting to a new system. They are a direct conversion, a parallel conversion, a phased conversion, a pilot conversion.

A new or upgraded information system undergoes a final test called acceptance testing. It includes the use of real data to demonstrate that the system operates correctly under normal and peak data loads. The term “maintenance phase” is a bit misleading because it seems to imply that the information system is maintained in a static state. On the contrary, during the maintenance phase, an information system is likely to undergo many changes to meet an organization’s needs. They can include the following: upgrades to operating system and commercial software, user interface revisions to make the system easier to use, application software revisions to fix bugs and add features, hardware replacements to enhance performance, security upgrades.

To combat an escalating number of viruses, worms, Denial of Service attacks, and intrusions, security has become a top priority for the maintenance phase of an information system’s life cycle. Maintaining security is an ongoing activity. A system operator and a systems programmer are responsible for system maintenance. Even after in-depth training, employees sometimes forget procedures or have difficulty when they encounter a new set of circumstances. Many organizations establish a help desk to handle end-user problems. For example, suppose you encounter a problem with an update procedure and call the help desk. The help desk technician begins to troubleshoot the problem and soon realizes that it is caused by a programming error not caught during system testing. This bug is recorded in a “bug report” that is routed to the programming group, which can determine its severity and take steps to fix it.

 

Comprehension check. Match the beginnings of the sentences in the first column with the endings in the second.

1. Unit testing and integration testing are 2. When a problem is discovered during unit testing or integration testing 3. System conversion refers 4. When converting data from an existing computer system to a new system 5. A system operator and a systems programmer are 6. The help desk technician begins   a) responsible for system maintenance. … a programmer typically writes. b) conversion software to read the old data and convert it into a format that is usable by the new system. c) … usually performed in a test area. d) … the team must track down the source of the problem and correct it. e) … to troubleshoot the problem and soon realizes that it is caused by a programming error not caught during system testing. f) … to the process of deactivating an old information system and activating a new one.

 


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