Modern Systems Analysis and Design Chapter 2

Modern Systems Analysis and Design, Chapter 2: The Origins of Software

• Historically, software development for a corporate information systems department was primarily done in-house.
• Now, software development involves components from external sources.
• Much in-house coding involves integrating components from external sources.
• Six sources of software:
  • Information technology service firms
  • Packaged software providers
  • Vendors of enterprise-wide solution software
  • Cloud computing
  • Open-source software
  • In-house development
• Methods of evaluating software from various sources are available.
• Outsourcing is the practice of transferring responsibility for some or all of an organization's information systems applications and operations to an external firm.
• Shell Oil's outsourcing spending totalled $3.2 billion in 2008.
• Outsourcing vendors (2008-2011): EDS, T-Systems, AT&T, IBM, Logica, Wipro, Accenture.
• Reasons to outsource:
  • Cost-effectiveness (economies of scale).
  • Filling in deficiencies in in-house knowledge.
  • Freeing internal resources.
  • Reducing time to market.
  • Enhancing process efficiency.
  • Outsourcing system development as a non-core activity.
  • Political considerations (e.g., labor disputes).
• Top outsourcing countries (2014 A.T. Kearny report): India, China, Malaysia. Top 10 in Asia, Latin America, Europe, and Africa.
• U.S. firms are increasingly shifting to nearshoring (same time zone, lower labor costs).
• Examples of leading software firms and their specializations are listed in Table 2-1.
• Information Technology (IT) service firms help companies develop customized internal information systems and run applications for customers. Additional services include management, accounting, and financial functions.
• Packaged software producers offer a range of software. From broad-based packages (e.g., general ledger) to niche packages (e.g., day care management), catering to various market segments.
• Packaged software is pre-packaged, "off-the-shelf", and turnkey software (non-customizable).
• Off-the-shelf software typically meets 70% of organizational needs. Software runs from microcomputers to large mainframes.
• Enterprise Resource Planning (ERP) systems integrate individual traditional business functions into modules for seamless cross-functional transactions. SAP AG is a leading ERP vendor.
• Cloud computing provides computing resources (applications) over the Internet. Customers avoid investing in and maintaining computing infrastructure. Pay-per-use or monthly/yearly licenses are common. Cloud computing examples: Google Apps, Salesforce.com, Microsoft Azure platform, Amazon.com.
• Open-source software is available free of charge, with source code. It's developed by communities of interested individuals and performs commercial software functions. Examples: Linux, MySQL, Firefox.
• Benefits of open-source software: -Free software and source code. -Usually freely available. -Developed by passionate individuals. -Maintained and improved by communities.
• How open-source software providers generate revenue: -Providing support/maintenance services. -Selling more comprehensive versions of the free software.
• In-house development is most effective when sufficient expertise with the target platform exists. Maintenance burden is often greater than other approaches in-house development. Hybrid methods (involving a mix of purchased and in-house components) are common. Comparison of various software-building strategies is found in Table 2-2.

Selecting Off-the-Shelf Software

• Cost considerations involve comparing in-house development costs to the costs of purchasing or licensing software.
• Functionality includes tasks the software can perform (mandatory, essential, and desired features).
• Vendor support includes the type and cost of support.
• Vendor viability involves assessing if the vendor will adapt to evolving systems software and hardware.
• Selection factors also include flexibility (ease of customization), documentation (manuals and technical information), response time (speed of interactive responses), and ease of installation.

Validating Purchased Software Information

• Requests for proposal (RFPs) are submitted to vendors. These documents specify a company's needs.
• Information sources for validating a software package acquisition can include vendor proposals, running the software through tests, feedback from others who utilize the system, independent testing services, and customer surveys. Articles in trade publications can sometimes be misleading (e.g., manufacturer-inserted bias).
• RFPs (sometimes called Request for Quotes or RFQs) help analysts identify the best selection.

Reuse

• Reuse involves utilizing previously written software assets (objects/components) in new applications. This is commonly applied to object-oriented and component-based development.
• Object-oriented development is based on object-classes encapsulating data and behavior of common organizational entities (e.g. employees).
• Component-based development uses components varying in size (from objects to software for single business functions).
• Reuse can increase productivity and reduce rework, but can be affected by technical or organizational issues, including the availability of component libraries and organizational commitment.
• Costs and benefits of reuse are highlighted in Figure 2-5.
• Three steps involved in implementing software reuse:
  • Abstraction - designing reusable software.
  • Storage - making software resources accessible.
  • Recontextualization - making the software understandable to developers.
• Approaches to reuse range from ad-hoc to facilitated, managed, and designed. These approaches vary in the degree of reuse, commitment levels, policies, and costs, as outlined in Table 2-3.