A variable access associative memory chip for flexible searches in RAM

This paper discusses the design and experimental implementation of a new type of random access memory (RAM) chip that is also a flexible associative memory, or content-addressed memory. It allows a rapid search for strings of characters that match the test string, and in which either the memory strings or the test string, or both, may contain “variable” indicators. The memory is a type of associative memory that matches all bytes of RAM simultaneously with a given byte of the test string and advances a flag in each RAM byte that is a direct match, or that is a potential match following a variable indicator. After requesting one pass of the test string using direct memory access (DMA), the program can then retrieve the address of each matching string, in turn, that falls in specified areas of RAM. We call it a “variable” access memory because it can access data in a variety of ways: as a normal RAM, as an associative memory, and as an associative memory with variables. For example, it can perform rapid searches in various types of tables the program must access repetitively when processing nested data in knowledge-based systems, expert systems, language translation, and similar applications