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Associative Memory System using Latchable Search Drivers

IP.com Disclosure Number: IPCOM000077452D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Davis, DE: AUTHOR [+2]

Abstract

Described is an associative-memory configuration which eliminates the requirement for separate data bus receivers, bus registers and search drivers/ decoders by combining these functions into one circuit. The output registers are also eliminated, allowing the output data to appear directly on the bus where it can be sampled during the appropriate READ time slot or in the case of cascaded systems, be stored in the latchable search drivers of the following stage for use in subsequent search arguments.

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Associative Memory System using Latchable Search Drivers

Described is an associative-memory configuration which eliminates the requirement for separate data bus receivers, bus registers and search drivers/ decoders by combining these functions into one circuit. The output registers are also eliminated, allowing the output data to appear directly on the bus where it can be sampled during the appropriate READ time slot or in the case of cascaded systems, be stored in the latchable search drivers of the following stage for use in subsequent search arguments.

The configuration is depicted in the figure and operates as follows:

When control S goes negative, the right-hand current switch of the latchable search drivers (e.g., transistors 1, 2 and 3 of the first bit position) are activated, thus transferring the true and complement of the bit 1 pad data onto the collectors of transistors 1 and 2, respectively. When S returns positive, the latched current switch comprising transistors 4, 5 and 6 is enabled which retains the pad data in a latched condition on the search lines, which are now independent of any change in pad data. The collectors of the search drivers are dotted to achieve the "one out of four" coding tabled below. Pad Bit 1 Pad Bit 2 Search Lines

1 2 3 4

+ + - - - +

- + + - - -

+ - - + - -

- - - - + -. The result of the search operation causes the appropriate word line to be raised in the READ array when the READ ENABLE control is present, causing the read...