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DETAILED SPECIFICATIONS. Chapter-3. DETALED SPECIFICATION. The preliminary design activity provides a high-level conceptual description of how the system should work. In Detailed Specification, the design team creates a detailed description of the system on paper.
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DETAILED SPECIFICATIONS Chapter-3
DETALED SPECIFICATION The preliminary design activity provides a high-level conceptual description of how the system should work. In Detailed Specification, the design team creates a detailed description of the system on paper.
ACTIVITIES IN DETAILED SPECIFICATIONS Three major activities occur:- • Specific Definition of Requirements • Selection of Software Source • Selection of Equipment Source
EQUIPMENT SELECTION • Possible suppliers are identified by the design team after studying the trade journals and subscription services. • Then these vendors are evaluated.
Subscription Services • Provides an efficient way to know the kind of available equipment. • Provided by companies that keep an eye on industry and observe changes in technology. • These companies compile up to date technical information in notebooks. • They compile info in such a way that makes comparison easier. • Study team reviews specs and then select.
Evaluation of Equipment Vendors • Two common approaches exits for vendor evaluation. • RFQ minimum configuration defined by design team • RFP configuration is left for organization
Criteria for Equipment Evaluation Design team evaluates the vendors’ proposals from view point of the following five factors:- Equipment Performance Adaptability Vendor Support Availability Cost
REQUIREMENTS DEFINITION In preliminary system design, the logical requirements for the proposed system were defined. Here these requirements (output, data, input, processing) are specified in detail.
Output Specification • Output produced by the system is in the form of display screens or reports. • In preliminary system design, the information contents of output were determined. • In detailed design, the layout of these output is decided. • The design team produces sample screens and reports called screen layouts and report layouts. • These sample layouts are used as examples in documentation.
Data Specification • Data is contained in records and presented in the form of reports and display screens. • Manual files store data on papers, computer files store it on magnetic disks or tape. • Each data record is described in detail, its purpose is listed, its data items are identified and data organization is described. • Number of occurrences of each record is estimated. • Retention & backup procedures are specified. • Retention shows how long data must be maintained for tax and audit. • Backup shows how frequently copies of data are stored.
Input Specification • Inputs include source documents. • Design team determines how each source document looks like. • For example, what data items are included in each source document such customer name, product price, product quantity, order date etc. • Sample documents are prepared by design team to show the arrangement of these data items. • Users review these samples to suggest any changes. • In cases of direct data entry, design team decides how captured data is converted into a magnetic record.
Computer Program Specification • A programming work package is produced by system analyst which contains description of each program logic, its inputs and its outputs in written form. • This package is later used by programmer. Program Narratives: program’s purpose, frequency of its execution, data records accessed by it, its inputs & its outputs. Structure Charts: modules & their hierarchy, rectangle is used to show a module in structure chart, shows program logic. Pseudocode: also used for module description, an informal language to describe program working, without any syntax.
Manual Procedures • Many processes are performed by people. • The steps of these manual procedures are described in document form. • It is also specified as who will perform this procedure. • The frequency of apply the procedure is also estimated.
SOFTWARE SPECIFICATION In detailed specification, design team takes the final decision about software source. If in-house development is decided, then development plan must be created. If software packages are to be purchased then package must be selected and plan be developed for modifications.
Planning Software Development Software development is a time consuming task. So adequate planning is necessary. Development plan contains estimates for time requirements, assigns personnel to programming tasks and describes software standards. Estimate Time Requirements Assign Personnel Software Standards
Software Acquisition Software packages are available that have similar requirements. They can also be purchased and modified if necessary. Seven-step procedure for selecting a package Review the Requirements Identify Available Packages Narrow the Choice Perform Detailed Comparisons Talk to Users Conduct Benchmark Tests Select a Package
REPORT TO MANAGEMENT At the end, a detailed report is prepared which contains the following information:- • Executive summary describing objectives, scope, major features of system • Documentation package • Exact specifications of input, output, processing and files • Necessary equipment, programs and their sources • Costs of installation and operation
AUDIOR INVOLVEMENT IN SYSTEM DESIGN Auditor’s involvement in System Design is very important. Auditor performs two major functions:- • Evaluating the detailed specifications to recommend improvements. 2. Considering how to introduce audit modules into the system’s programs.
Specifications Review Evaluating the adequacy of new system’s Audit Trail and Internal controls is necessary. AUDIT TRAIL: • It is produced by info contained in reports and files. • Tracing individual transaction to financial statement amount. • Tracing a financial statement amount to an individual transaction. INTERNAL CONTROLS: • These are measures taken to prevent or detect erroneous data , to secure data from theft, to secure data from unauthorize change. • Auditor examines proposed procedures for file backup, file retention and for correcting erroneous transactions.
Reports Reports are reviewed to verify that these reports include the necessary information required for auditability and control. A report that discloses journalized transactions should identify document numbers for all the transactions. A printout of a ledger should indicate a source for all journal postings making up the ledger balance. These enable the auditor to trace from a ledger total to an individual transaction.
Processing Steps Auditors review program narratives and procedures manuals written in documentation package. Then auditors suggest control procedures that need to be added to them. For example controls are added to compare grand total of all transactions of all batches with individual batch totals and if there is difference it should be included in the controls report.
Data Files Data file specifications are also reviewed. Auditors evaluate the control measures ensuring the security and accuracy of data and verify that data items included in the file provide an audit trail. Auditors also check that if files are destroyed unintentionally, the backup procedures can reconstruct the files.
Equipment Selection The selected hardware choices are examined by auditor to ensure that these choices can fulfill management’s desires. They evaluate the sufficiency of equipment and check that equipment is not excessive than demands.
Audit Modules Audit modules are embedded into system’s programs for producing accurate data. An audit module is segment of program that enable auditors to examine transactions as they are processed.
