In Belfast it is always easier to remember than it is to forget. The voodoo of party tune and rebel ballad make sure of that. But never has there been such a revival of old songs and the writing of new ones as there has in the past six years since the modern ' troubles ' began. Dates, battles, tribal scores still to be settled in the fulness of time - all, it seems, have to be rushed into verse and, frequently, the same tunes are employed by both sides. Alongside the records and the broadsheets stand the ' souvenirs,' from the Maze Prison, Long Kes.h - plaques and carved guns.