Abstract: A system for providing a plurality of timers to perform the timing of event occurrences wherein, for each event, there corresponds a timer control block which stores in its time-flag field (Tf) an indication of whether the timer control block is chained or unchained, running or stopped, in its time-out field (Tv) the expiration time interval and in its time-stamp field (Ts) the current time as a reference at each interruption. The timer control blocks are chained by a one-way link according to their expiration times in such a way that each timer chain contains the timer control blocks whose events will occur at the same time. A cyclic table of index values classifies the timer chains according to their expiration times.