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Checking Associative Store Address Line Drivers

IP.com Disclosure Number: IPCOM000074698D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Foster, RL: AUTHOR [+2]

Abstract

In associative stores it is important to check that none of the interrogating address line drivers have failed to function. In the associative store shown one word is used to check the address line drivers.

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Checking Associative Store Address Line Drivers

In associative stores it is important to check that none of the interrogating address line drivers have failed to function. In the associative store shown one word is used to check the address line drivers.

The store comprises N columns of M cells. Each column stores one word and each cell stores one bit of a word. Each cell 1 has two-bit position 3 represents a binary 1, and a '0' in position 2 and a '1' in position 3 represents a binary 0. The store is interrogated by M pairs of address lines 4a and 4b. Lines 4a are used to select bit positions 2 and lines 4b are used to select bit positions
3.

In operation, line 4a is used when a bit position of a word is to be interrogated for a '1' and line 4b is used when a bit position of a word is to be interrogated for a 'a'. When position 2 or 3 has been selected, a mismatch signal is produced if that position stores a '0,. The mismatch signal is amplified by sense amplifier S and applied to a NOT OR gate 6, which indicates a match if none of the cells in its associated column produced a mismatch signal.

Word column N is used for checking the drivers of address lines 4a and 4b. Each bit position in column N stores a '0', so that a mismatch signal will be produced by every interrogation provided a driver has not failed. The outputs of all the cells of column N are applied to a NOT AND gate which indicates a failure of one or more of the drivers.

The appropriate connections...