Alpha (programming system)

System development

Development of the system of ALPHA began with creation of language  — it was characteristic of traditions of the programming programs. This language makes a start from the initial version of the ALGOL 60  — a so-called ALGOL 58. The group directed by Yershov conducted development in parallel with the international group developing the ALGOL 60. In many respects works of the specified groups were coincident and therefore after publication of the description of the ALGOL 60 the new, created by Yershov's group language was formulated as expansion of the ALGOL 60. This language carrying the preliminary names "Input", "Siberian" finally affirmed under the name Alpha language.

In Alpha language the concept of multidimensional values is introduced for the first time and transactions over them, including designing transactions are defined. All this entered standard baggage of concepts of the modern languages, such as PL/1, ALGOL 68, Hell. Also such, natural concepts to the modern languages as a variety of cycles, a task of starting values expressions were for the first time entered. But, in essence, not repeated properties of language transfers and upper (temporary) indexes were interesting. In the metameans language for the first time went beyond context-free grammars.

The system of ALPHA was the first in world practice optimizing programming system for the languages, more difficult, than the Fortran. The English project (Hawkins and Haksteybl) existing at the same time for the ALGOL 60, similar to Alpha on functionality, was not finished. It is important to note it because the possibility of existence of translators for the languages, more difficult, than the Fortran, with acceptable efficiency of object programs at that time many was disputed. The system of ALPHA became the constructive proof of such opportunity, and it is essential because removed barriers on the way of creation of new, semantic more rich languages. The initial rotaprintny edition on a system appeared in  1964.

Scientific value of work

Works on the system of ALPHA made a large contribution to methodology of the optimizing broadcasting. The multipass scheme of broadcasting focused on optimization was offered and implemented, the optimizing conversions of intermediate submission of the program are introduced in practice of optimization of programs for the first time, the intermediate submissions of the program focused on optimization algorithms are selected and constructed.

The methods of economy of memory implemented in a system by ALPHA developed by Yershov represent the theoretical and practical base of the subsequent works on memory economy. Later Yershov entered a concept of information software graph as the model suitable for determination of such conversion as global economy of memory, the problem of economy of memory was reduced to the known problem of a coloring of the graph, together with   G.I. Kozhukhin the foundation of a heuristic algorithm close to optimal a coloring of the graph was laid. Yershov gave bases of a complete theory of economy of memory. These works defined not only works on memory economy, but also other researches on optimization of programs, in particular gave a good example of creation of practical theoretical models for optimization of programs.

Further works of Yershov on the optimizing broadcasting led to emergence of widely known and used still Alfa-6 system.