Computer software component

Safety-critical computer software components Those computer software components (processes, functions, values or computer program state) whose errors (inadvertent or unauthorized occurrence, failure to occur when required, occurrence out of sequence, occurrence in combination with other functions, or erroneous value) can result in a potential hazard, or loss of predictability or control of a system (MIL-STD-882). 

Figure 1 lists the major industrial processes that use thermodynamic data and the kind of data that are relevant. The design and use of distillation columns are the largest consumers of thermodynamic data. The feed stream to most industrial columns contains at least several components. The predication of the operating characteristics of such columns requires complicated calculations, and much computer software has been written... 

Fragment constant The partition coefficient is expressed as the sum of its component fragments log P=([jj an-fn where (a) is the number of fragment (f) of type (n) in the molecule Adjustment for steric effects, bond type and different interactions gives a complex calculation usually accomplished with computer software... 

The main areas of application for more generalised models have, until recently, been restricted to binary and ternary systems or limited to ideal industrial materials where only major elements were included. The key to general application of CALPHAD methods in multi-component systems is the development of sound, validated thermodynamic databases which can be accessed by the computing software and, until recently, there has been a dearth of such databases. 

The following practices are applicable to all software components considered part of all computer systems performing regulated operations ... 

The installation of software components that are part of a computer system are qualified according to procedural controls. 

The system operational qualification performed on the computing technology provides documented evidence of a high degree of assurance that the hardware and software components perform as required by the system specification. This includes the verification that each unit or subsystem of the system operates as intended throughout all anticipated operating ranges. Appropriate personnel must conduct the system operational qualification. 

The practices contained in this section apply to all operating systems and system software components that are considered part of a computer system. 

All computer systems performing regulated operations must be validated. To support computer systems validation, operating systems and system software components are installed according to the manufacturer s instructions. The installation verification includes documentation gathered during the verification activities. 

Unit A separately testable element specified in the design of a computer software element. Synonymous to component, module (IEEE). 

The Monte Carlo exposure calculations described in this chapter are carried out with a flexible computer software program named DistGEN (Sielken Inc., 1995). This program allows exposure equations to be specified in the general computer language called FORTRAN, so they can have practically any form. Furthermore, the user-specified distributions for the components of the exposure equations can be selected from a wide variety of classical statistical distributions (normal, log-normal, etc. with user-specified parameter values) or from sample data (either the sample... 

Cichocki, T. and J. Gorski, Failure Mode and Effect Analysis for Safety-Critical Systems with Software Components, in Floor Koomneef, Meine van der Meulen (eds.) Computer Safety, Reliability and Security, Proceedings of 19th International Conference SAFECOMP 2000, Rotterdam (The Netherlands), October 24—27, 2000, Springer Lecture Notes in Computer Science 1943, p. 382-394. 

Most large networked systems embody human beings as, in effect, system components , alongside the hardware and software components, though as indicated above such humans may become actively involved only when things go wrong with the computers and their communication. In other cases, there may be a deliberate decision to sub-divide some overall system task into activities that can be readily automated, and those that are best left to human beings to carry out. Systems that incorporate human components in either of these ways are termed here computer-based systems. 

If we establish a relation between Fig. 1.2 and the computer software that assists the operation of the filtration plant, then we can say that this software can be the result of an assembly of mathematical models of different components or/ and an assembly of experimentally characterized components. 

Most computer systems will have a number of software components falling into several of these categories, as illustrated in Table 5.1. 

Failure to validate computer software used as part of the quality system for its intended use according to an established protocol as required by 21 CFR 820.70(i). For example, the data in the Excel spreadsheet identified as a hit list of top nonconforming components contains 16 record counts for part number 8601618 DC converter failures compared to 18 record counts for part number 860168 DC converter failures in the dbase database. The spreadsheet is used for management review of component suppliers for all components. 

Prospective validation is executed and completed before release of the computer system for use and operation in the live environment and will encompass the complete system, including all hardware and software components and interfaces, and its associated operational and maintenance environment. 

In this context it should further be pointed out that a commercial method development computer software package (DRYLAB) has been successfully applied to optimize enantiomeric separations of a multi-component amino acid sample utilizing isocratic and gradient elution techniques 389. ... 

For optimising two parameters at a time, one of the simplest, and easy to use computer software packages is DryLab, produced and marketed by LC Resources. Data from just two runs is used to predict both isocratic and gradient conditions. Usually the two runs are gradients in which the % organic component in the mobile phase is varied with time. The peak... 

Validation, however, means different things to different people. Some companies and their Information Technology Group (ITG) will dismantle the computer and its software components, reconfigure them, test them, and then reinstall them. Others will take a more realistic approach and work on the basis that the computer was brought in for a specific task and, is considered validated provided that task is completed with the aid of the computer in a reproducible and acceptable manner. 

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