In order to be truly portable, a program must be tolerant of a wide range of development and execution environments, and a parallel program is just one which must be tolerant of a very wide range. First, the term ''tolerant programming'' is defined. Then, a formal model called F-Nets is described in which parallel algorithms are expressed as folded partial-orderings of operations, and this is argued to provide a suitable framework for building tolerant programs. Finally, Software Cabling (SC), a very-high-level graphical programming language, demonstrates how many Of the features normally expected from today's computer languages (e.g. data abstraction and data parallelism) can be obtained within the F-Net paradigm.