Many languages, including Fortran, and machines such as most minicomputers have little or no built-in character manipulation capability and yet are often required to process character information. This paper discusses the programming of character processing in such integer environments. Character representation, string-to-word coordinate transformation, packing, and unpacking using several arithmetic schemes are discussed with special attention to program portability. Several Fortran subroutines are presented culminating in BYTRAN, a set of portable Fortran subroutines that simulate the string structures and operators of the PL/I language.

A principle of scheduling is presented that includes a wide class of time and space allocation problems met in time sharing and virtual systems. Its essence is a method, based on symmetry, to use any of several rules for admission-to-service in a single server system to derive a space-replacement rule. This method, called complementary replacement includes several known job dispatching rules as well as some page-replacement algorithms such as the MIN and LRU (last-recently-used). A fundamental but unsolved problem with the principle is its range of applicability and the conditions under which it guarantees an optimum.

A classification of the objectives and types of parallel processing gives the context of the prinicipal subjects of this paper. A compiler and machine organization which are capable of detecting opportunities for parallel processing in algebraic expressions and executing these by multiple processing units operating concurrently are described. The compiler algorithm, based on a tree structure of algebraic expressions, translates the expression into an object program containing concurrency groups of instructions. Within each such group. all of the instructions can be executed at the same time. The machine organization (described in a schematic way) includes a simple control for executing the object program by allocating instructions to processors within a group and interlocking advance to the next group until execution of the current group is completed.