Design considerations of a database computer are presented in this paper. The overall architecture of the computer as well as the organization of its individual components are discussed. Several key concepts which are vital to database management are incorporated in the design and organization of the components. The concepts of tracks-in-parallel read-out and logic-per-some-track processing are provided in an on-line database store for the purpose of achieving high-volume content-addressability. The use of auxiliary information about the database for access precision and control has resulted in the design of a structure memory, an array of content-addressable memory and processor pairs, for large collections of indices. The choice of technologies for the implementation of these components is considered in terms of their cost and performance. Modified moving-head disk technology is chosen in order to support the very large on-line database store. Emerging technologies such as magnetic bubbles and CCD's are chosen for the structure memory on the basis of their matching performance with the on-line database store and their capability for parallel-in-blocks-and-serial-within-block processing. Five other important components are also disdissed in the paper. Their role in the database computer and relationship with the structure memory and on-line database store are delineated.

The design of a mass memory for a database computer (DBC) is described. The DBC, a specialized back-end computer, is capable of managing 10**9 to 10**10 bytes of data and can support multiple data models with minimal software in the front-end computer. The design is based on moving-head disk technology which is perceived to be the most cost-effective technology for supporting such large volumes of on-line data. The design calls for certain key modifications in existing modes of disk component usage in an effort to incorporate a high degree of intelligence in the device and to enhance its throughput. These modifications pertain to activating concurrently all of the read/write heads available on an access mechanism and to the processing of data on-the-fly by associating a processing element with each read/write head.