Browse Prior Art Database

Simultaneous Read and Write

IP.com Disclosure Number: IPCOM000074907D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Hardwick, IR: AUTHOR [+2]

Abstract

In a monolithic associative store, the potentials on word lines W are the same for reading and writing; the operation being determined by bit logic, not shown, connected to bit lines B0, B1. In one or more columns of the store an extra latch L is provided to enable the states of the selector triggers S, whereby words are selected for accessing, to be written into the columns independently of whether a read or write operation is taking place on the other columns. The store has a two-phase cycle: in phase P1 selector triggers S are set, typically by an associative search operation which generates signals on the word lines W, to select words for a read or write operation during phase P2.

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Simultaneous Read and Write

In a monolithic associative store, the potentials on word lines W are the same for reading and writing; the operation being determined by bit logic, not shown, connected to bit lines B0, B1. In one or more columns of the store an extra latch L is provided to enable the states of the selector triggers S, whereby words are selected for accessing, to be written into the columns independently of whether a read or write operation is taking place on the other columns. The store has a two-phase cycle: in phase P1 selector triggers S are set, typically by an associative search operation which generates signals on the word lines W, to select words for a read or write operation during phase P2. If a write selectors operation is required, latch L is set by a WS signal at the end of P1 and applies suitable potential to the bit lines to which it is connected to cause a write operation in the column, resulting in a 1 being written in those words with selector triggers set. Alternatively, 0 can be written, or a choice between 1 and 0 can be provided.

One application of writing selectors is to enable subselection or other logical combinations from among a selected group of words.

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