Legacy Systems: Definition, Types, Advantages & Disadvantages, Examples, Modernization
What is a legacy system?
Definition: A legacy system refers to outdated computer software, equipment, hardware, or technology that is still used in daily operations. These systems lack support, maintenance, and future development. Examples include older operating systems like Windows XP, Windows Vista, and Windows 7. While the legacy system may still be functional, it often hinders the organization’s ability to stay competitive in the market due to its limitations.
Legacy Applications Definition: A legacy application, in the realm of software development, refers to a piece of software that has been in use for a significant period, often built on outdated technology or architecture. These applications typically have been in operation for many years, serving critical functions within an organization.
Certainly, there are several alternate names or terms that are often used interchangeably with “legacy system” in the context of information technology:
Outdated System
Obsolete System
Aging Infrastructure
Heritage System
Antiquated System
Vintage Technology
Traditional System
Old-School System
Historical System
Dated Technology
Inherited System
Ancient System
Why are legacy systems still used?
Legacy systems were built for specific purposes, such as controlling a factory or managing an airport. They may have been designed for one purpose but are now used for a different purpose, such as customer relationship management (CRM) software that was originally designed for sales and marketing applications.
Legacy systems and applications continue to be used for several reasons, despite their outdated nature. Here are some common reasons:
Investment Protection:
Companies may have made significant financial investments in developing or customizing legacy systems. The cost of migrating to a new system can be prohibitive, making organizations hesitant to abandon their existing infrastructure.Business Critical Processes:Legacy systems often support critical business processes that are deeply embedded within an organization. Replacing these systems may disrupt essential operations and jeopardize business continuity.
Fear of Change:Resistance to change is a common human trait, and this extends to organizational structures and systems. Employees may be comfortable with familiar interfaces and workflows, making the prospect of transitioning to a new system daunting.
Obsolete Technology:Some legacy systems may be built on outdated technology or programming languages that are no longer widely supported. The lack of available expertise in these technologies makes migration a complex and risky endeavor.
Lack of Documentation:Over time, documentation for legacy systems may become scarce or non-existent. This lack of documentation makes it challenging to understand the system’s intricacies, leading to uncertainty about the impact of migration.
Examples of Legacy Systems
Legacy systems can be found in various industries and domains. Here are a few examples:
1. Mainframe Computers Mainframes are a classic example of legacy hardware. While they still power critical functions for many organizations, their technology is decades old. Many financial institutions, for instance, rely on mainframes for their core banking systems.
2. COBOL Applications COBOL (Common Business Oriented Language) is a programming language developed in the 1950s. Many organizations still use COBOL-based applications for functions like payroll processing, despite the language’s age and declining popularity.
3. Old ERP Systems Enterprise Resource Planning (ERP) systems are crucial for managing business processes. Some organizations continue to use outdated ERP software versions because migrating to a newer system can be complex and costly.
4. Legacy Database Systems Databases using older technology like dBase, FoxPro, or even early versions of SQL databases may still be in use for specific applications, despite the availability of more modern database solutions.
5. Custom-Built Systems Some organizations have custom software applications or systems developed in-house using technologies that have become outdated over time. These systems are often challenging to maintain and enhance.
Types of Legacy Systems
Legacy systems can be categorized based on different criteria. Here are several types:
1. Hardware Legacy Systems These are legacy systems that involve outdated hardware components. Examples include old mainframe computers, proprietary hardware, and discontinued server architectures. These systems may require specialized maintenance and expertise.
2. Software Legacy Systems Software legacy systems are characterized by outdated software applications and codebases. This category includes applications developed using deprecated programming languages, obsolete software libraries, or operating systems that are no longer supported.
Read full blog here- Complete Overview of Legacy Systems