RTL/2Real Time Language. A small real-time language based on ALGOL 68, with separate compilation designed by J.G.P. Barnes of ICI in 1972 as a successor to RTL/1. A program is composed of separately compilable modules called "bricks" which may be datablocks, procedures or stack. A stack is a storage area for use as a workspace by a task. The language is block-structured and weakly typed. Simple types are byte, int, frac and real. There are no Booleans. Compound types may be formed from arrays, records and refs (pointers). There are no user-defined types. Control statements are if-then-elseif-else-end, for-to-by-do-rep, block-endblock, switch, goto, and label variables. ["RTL/2: Design and Philosophy", J.G.P. Barnes, Hayden & Son, 1976].