The routines are divided by function into the following subsets:
a) INIT/CLOSE - initialise and tidy-up internal system b) VALID,RELEASE - check/release from internal system c) CHKxxx - check existence of an SSDS object d) LOCxxx - get locator to an SSDS object e) MAPxxx - map a field data/error object f) UNMAPxxx - unmap a field data/error object g) GETxxx - get value of field item/parameter h) PUTxxx - write value of field item/parameter/NSRC i) CRExxx - create a field/field error/NSRC