A first version of UNCOL

• Authors: T. B. Steel, Jr.
• Venue: IRE-AIEE-ACM '61 (Western) Papers presented at the May 9-11, 1961, western joint IRE-AIEE-ACM computer conference
• Year: 1961

UNCOL--UNiversal Computer Oriented Language--is being designed as an empirical, pragmatic aid to the solution of a fundamental problem of the digital data processing business: automated translation of programs from expressions in an ever increasing set of problem oriented languages into the machine languages of an expanding variety of digital processing devices. By application of a program called a generator, specific to a given problem language, program statements in this problem language are transformed into equivalent UNCOL statements, independent of any consideration of potential target computers. Subsequently, without regard to the identity of the original problem language, the UNCOL statement of the problem is processed by a program called a translator, which is specific to a given target computer, and the result is an expression of the original problem solution in the machine language of the desired processor. The advantage of this apparent complication over the current procedure of employing a program called a compiler for direct transformation from problem language to machine language is evident when one examines the number of languages and machines involved and the not inconsiderable expense of translation program construction. If there are M problem languages and N machines, then M+N compilers are required and only M+N generators and translators. In order to arrive at sensible specifications for UNCOL, certain limitations in its scope are essential. Accordingly, UNCOL is designed to cope with only those problem language and machine language characteristics that can reasonably be expected to enjoy general use in the next decade. Any broader approach shows promise of leading to elegant, impractical results. A glance at the preliminary specifications for UNCOL shows a language akin to a symbolic assembly language for a register-free, single address, indexed machine. The specific commands are few in number and simple in construction, depending on a special defining capability for the expression of more elaborate instructions. The data referencing scheme is complex, allowing the application of a signed index to the primary address, and permitting both the primary and index parts to be delegated to an indefinite level. Each item of data, either input or calculated, must be described as to type, range precision and the like by special data descriptive syntactical sentences in the language. These descriptions, additionally, provide information concerning ultimate storage allocation as well as indicators of contextual meaning for the explicit commands. Supplementary to the instructions and data descriptions are certain declarative sentences, inessential to the explicit statement of the problem solutions being translated, designed to provide information useful to the translator in the introduction of computational efficiency into the object program.