Old Payroll Systems

In older payroll systems (and indeed many other systems) storage was at a premium so they couldn't do some things we can do easily now. One of these is manage transactions historically.

All the older systems tend to treat data items as having only a single dimension - only the current value is stored and anything that went before is lost (or hard to retrieve). This makes it easier to deal with, but ultimately less capable.

These days we can use the history of a range of data items to do more complex payroll calculations.