Maintenance of software

Prepare procedures controlling the development and maintenance of software used in measurement systems. 

Guidelines for the application of ISO 9001 to the development, supply, and maintenance of software. 

Primary SLC processes depend on who initiates or performs the development, operation, or maintenance of software products. These primary parties are the acquirer, the supplier, the developer, the operator, and the maintainer of software products. The primaiy SLC processes consist of acquisition process, supply process, development process, operation process, and maintenance process. 

ISO (2000), ISO 9000 Quality Systems —Model for Assurance in Design, Development, Production, Installation and Servicing, and ISO 9001-3 Quality Management and Quality Assurance Standards — Part 3 Guidelines for the Application of ISO 9001 to the Development, Supply and Maintenance of Software, International Organization for Standardization, Geneva. 

By its very nature, most software today is in a continual state of flux, reflecting not only the steady expansion of functionality driven by the fertile imagination of current users but also by the frenetic pace of improvements in IT hardware. This lack of stability enhances the importance of change control in any organization involved in the development and maintenance of software. Without formal change control, as many new errors are liable to be introduced into the software as the number of existing ones the maintenance effort intended to remove. 

As an overview of software system safety, the following is provided from the website of the U.S. Army Communications-Electronics Command (www.monmouth.army.mil/cencom/safety/main.htm). Software system safety optimizes system safety in the design, development, use, and maintenance of software systems and their integration with safety critical hardware systems in an operational environment. ... 

Computer engineering is a discipline that embodies the science and technology of design, construction, implementation, and maintenance of software and hardware components of modem computing systems and computer-controlled equipment. Computer engineering has traditionally been viewed as a combination of both computer science (CS) and electrical engineering (EE) http //www.eng.auburn. edu/ece/CCCE/CCCE-FinalReport-2004Decl2.pdf (accessed October, 22, 2010). 

In Chapter 2, Campos et d. Present an example of reverse engineering aimed at facilitating the development and maintenance of software applications that include a substantial user interface source code. Starting from the observation that understanding (and thus maintenance) of user interface code is highly challenging due to the typically non-modular structure of such code and its interactions with the remainder of the application, they present a technique and tool that is able to extract user interface behavioral models from the source code of Java applications, and show how these models can be used to reason about the application s usabiUty and implementation quality. 

CASE is the use of software tools to assist in the development and maintenance of software. All aspects of the software development life cycle can be supported by software tools therefore, the use of tools from across the spectrum can be described as CASE, from project management software through tools for business and functional analysis, system design, code storage, compilers, translation tools, test software, and so on. 

MOD91d] UK Ministry of Defence "Quality System Requirements for the Development, Supply and Maintenance of Software"... 

Procedures are required for the control and maintenance of inspection, measuring, and test equipment and to cover test software, not only for calibration. This section of the standard is often referred to as the calibration requirement but it goes far beyond mere calibration. In assessing compliance with section 4.11, there are at least 30 requirements to check (see the questionnaire at the end of this chapter) and calibration is only one of them. Figure 11.2 shows the processes needed to control, calibrate, and maintain inspection, measuring, and test equipment. The shaded boxes indicate interfaces with other processes. 

The requirement for procedures does not stipulate that they need to address all 30 requirements of this section of the standard. Procedures are required only for the control, calibration, and maintenance of these devices. The requirements in clause 4.11(a), for instance, requiring you to determine the measurements to be made and the accuracy required, are not requirements concerning the control, calibration, and maintenance of these devices. They are requirements concerning measurement. The procedure requirement only addresses the devices used for measurement and therefore does not apply to software other than software used for measurement. 

A difficult balance to maintain is the tightrope between custom and general operation. For minimum development and maintenance, the software should be very generalized. However, from the user s perspective it must be fast and easy to use. These two poles often conflict. If the in-house software is too general, one may as well buy a general commercial package. Too specific and it loses cost effectiveness. The end product must be generalized yet customizable to the requirements of the application. 

The computerized systems, both hardware and software, that form part of the GLP study should comply with the requirements of the principles of GLP. This relates to the development, validation, operation and maintenance of the system. Validation means that tests have been carried out to demonstrate that the system is fit for its intended purpose. Like any other validation, this will be the use of objective evidence to confirm that the pre-set requirements for the system have been met. There will be a number of different types of computer system, ranging from personal computers and programmable analytical instruments to a laboratory information management system (LIMS). The extent of validation depends on the impact the system has on product quality, safety and record integrity. A risk-based approach can be used to assess the extent of validation required, focusing effort on critical areas. A computerized analytical system in a QC laboratory requires full validation (equipment qualification) with clear boundaries set on its range of operation because this has a high... 

The key to making a large variety of software products in a short time is to make one piece of development effort serve for many products. Reuse does not mean that you can cut-and-paste code The proliferation that results, with countless local edits, rapidly becomes an expensive maintenance nightmare. 

Upgradability Can the system at runtime be upgraded with new features or versions of software without bringing operations to a halt Some systems must be operational continuously, and shutting them down for maintenance or upgrades is a serious matter. Systems that have a reflective core—the runtime keeps an explicit representation of the software structure, classes, interfaces, and so on and permits operations on that structure itself—can be the easiest to upgrade in this manner. 

A record of software acceptance testing and software maintenance or change control documents also ensures future software integrity. 

Immusoft is a software that has been developed to perform computer-driven assays in our microchips. This software has a user-friendly graphical user interface, and it enables control of the pump, the valves and the electrochemical detection system, as well as the development of specific assay protocols, the running of simultaneous or sequential experiments in eight parallel microchannels, the automatic read-out of the results and the processing of the obtained data. These different functions are managed by way of three main menus, named Method, Analysis and Results, and the software also comprises two additional items dedicated to the setting of the computing parameters and to the maintenance of the instrumentation. 

The practical approach we take is intended to increase efficiency and ensure that correct software development and maintenance is achieved. The topics addressed in this book are equally relevant to other type of software development industries. It is not the intention of this book to develop a paradigm or model for the regulated industry. 

As part of the conceptualization period, senior managers are presented with, and estimate the total effort to be expended (including maintenance for the project). The relative costs of each development stage are depicted in Figure 8-2.2 Note Maintenance of existing software can account for over 70% of all effort expended by a software organization and this cost will be passed on to the customer. 

The maintenance of computer systems becomes an essential issue, particularly when a new version of the supplier-supplied standard software is updated. A change control procedure must be implemented whereby changes in the software and computer hardware may be evaluated, approved, and installed. 

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