Typical lifecycles for main equipment types

Where:
Sale life = The period the commercial product is sold by the manufacturer
Support life=The period the manufacturer will provide support for the product through spares or call out
Extended support= The period by which the support for the product can be extended by other means, for example, by acquiring a sufficient stock of spares or using an alternative repair service.

Sale Support Extended
Equipment types (years) (years) support (years)
Mainframe computers
(eg DEC VAX or ALPA) 3 5 5
PC based (eg SCADA) 1 3 3
Distributed control systems (DCS) 10 10 5
Programmable logic controller (PLC) 10 5 2
VMS (IEEE 1014, 32 bit bus systems) 12 5 5