Browse Prior Art Database

Dynamic Decoder for Multiple Spares and Select Redistribution Within a Select Partition

IP.com Disclosure Number: IPCOM000047361D
Original Publication Date: 1983-Nov-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Aichelmann, FJ: AUTHOR

Abstract

Fault-tolerant techniques are used in memory systems to minimize the accumulation of faults which would otherwise result in unusable memory locations. These techniques involve sparing, data steering, or address reconfiguration for the dispersion of defects so that they do not accumulate within the same ECC word. The present disclosure provides a way that sparing and reconfiguration can be combined across a selection partition by the use of an M/N decoder instead of an I/N decoder. Fig. 1 shows a typical selection partition in a memory system. Fig. 2 depicts the use of an M/N decoder for the same selection interval which provides additional or spare selection elements. Fig. 3 provides an example of a M/N decoder (3 out of 6) substitution for an I/N decoder with 16 selectable elements.

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Dynamic Decoder for Multiple Spares and Select Redistribution Within a Select Partition

Fault-tolerant techniques are used in memory systems to minimize the accumulation of faults which would otherwise result in unusable memory locations. These techniques involve sparing, data steering, or address reconfiguration for the dispersion of defects so that they do not accumulate within the same ECC word. The present disclosure provides a way that sparing and reconfiguration can be combined across a selection partition by the use of an M/N decoder instead of an I/N decoder. Fig. 1 shows a typical selection partition in a memory system. Fig. 2 depicts the use of an M/N decoder for the same selection interval which provides additional or spare selection elements. Fig. 3 provides an example of a M/N decoder (3 out of 6) substitution for an I/N decoder with 16 selectable elements. The designation of the selectable elements for 16 selects and 4 assignable spares are tabulated in Fig. 3. Fig. 4 defines the redistribution properties for the example of Fig. 3 once defects or fault occur within the initial select interval. As shown, not only are spares available, but also the initially designated elements can be scrambled providing a sparing as well as a reconfiguration capability. As a result of selective switching or interchanging of the outputs (i.e., C1, C2 -- CN) of an M/N decoder, a combined sparing and reconfiguration occurs which can be used to minimize the effects of mu...