Before
Prior to the concept of ERP systems, it was not unusual for each department within an organisation to have its own customised computer system. For example, the human resources (HR) department, the payroll department, and the financial department might all have their own computer systems.

Typical difficulties involved integration of data from potentially different computer manufacturers and systems. For example, the HR computer system (often called HRMS or HRIS) would typically manage employee information while the payroll department would typically calculate and store paycheck information for each employee, and the financial department would typically store financial transactions for the organisation. Each system would have to integrate using a predefined set of common data which would be transferred between each computer system. Any deviation from the data format or the integration schedule often resulted in problems.

After
ERP software, among other things, combined the data of formerly separate applications. This simplified keeping data in synchronisation across the enterprise, it simplified the computer infrastructure within a large organisation, and it standardised and reduced the number of software specialties required within larger organisations.