Chain Loading - Chain Loading in BASIC Programs

Chain Loading in BASIC Programs

In BASIC programs, chain loading is the purview of the CHAIN statement (or, in Commodore BASIC, the LOAD statement), which causes the current program to be terminated and the chained-to program to be loaded and invoked (with, on those dialects of BASIC that support it, an optional parameter specifying the line number from which execution is to commence, rather than the default of the first line of the new program). The common data area varies according to the particular dialect of BASIC that is in use. On BBC BASIC, for example, only a specific subset of all variables are preserved across a CHAIN. On other BASICs, the COMMON statement can be used in conjunction with CHAIN to specify which variables are to be preserved as common data across a chain operation.

Chain loading permits BASIC programs to execute more program code than could fit into available program and variable memory. Applications written in BASIC could thus be far larger than the size of working memory, via a set of cooperating programs that CHAIN back and forth amongst themselves as program flow moves within the overall application.

Read more about this topic:  Chain Loading

Famous quotes containing the words chain, loading, basic and/or programs:

    Oft, in the stilly night, Ere Slumber’s chain has bound me, Fond Memory brings the light Of other days around me.
    Thomas Moore (1779–1852)

    Nitrates and phosphates for ammunition. The seeds of war. They’re loading a full cargo of death. And when that ship takes it home, the world will die a little more.
    Earl Felton, and Richard Fleischer. Captain Nemo (James Mason)

    Mental health depends upon the maintenance of a balance within the personality between the basic human urges and egocentric wishes on the one hand and the demands of conscience and society on the other hand.
    Selma H. Fraiberg (20th century)

    Although good early childhood programs can benefit all children, they are not a quick fix for all of society’s ills—from crime in the streets to adolescent pregnancy, from school failure to unemployment. We must emphasize that good quality early childhood programs can help change the social and educational outcomes for many children, but they are not a panacea; they cannot ameliorate the effects of all harmful social and psychological environments.
    Barbara Bowman (20th century)