In the late 20th century, time clocks started to move away from the mechanical machines to computer-based, electronic time and attendance systems. The employee registers with the system by swiping a magnetic stripe card, scanning a barcode, bringing an RFID (radio-frequency identification) tag close to a reader, entering a number or using a biometric reader. These systems are much more advanced than the mechanical time clock: various reports can be generated, including on compliance with the European Working Time Directive, and a Bradford factor report. Employees can also use the system to request holidays, enter absence requests and view their worked hours. User interfaces can be personalized and offer robust self-service capabilities.