DESIGN AND EVALUATION OF A GLASS DELAY LINE CONTENT-ADDRESSABLE MEMORY SYSTEM.
Abstract:
The high cost of content-addressed memories CAM can be reduced significantly by using a circulating memory system. With the circulating system comparison logic is shared by many memory locations to allow a reduction in cost. Three data organizations are described and evaluated and one is chosen as the best for implementation when 20 MHz, 100 microsecond glass delay lines are used. The complete design of a CAM system is described which has a 2048 x 35-bit capacity and is capable of searching the entire contents in 100 microseconds. Search criteria include equality and magnitude conditions. Operations include storing, fetching, and a variety of tagging functions. The described CAM has been constructed and installed as an operating addition to a general-purpose serial computer, the NEBULA. The CAM system has been a powerful addition to the NEBULA and a similar system could be a useful yet economical addition to any computer system. Author