Browse Prior Art Database

Stacking Single Inline Memory Module Card

IP.com Disclosure Number: IPCOM000113893D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Coteus, PW: AUTHOR

Abstract

Described is a technique for increasing the memory storage of a computer system by stacking memory cards. Personal computers have the feature that memory, typically Dynamic Random Access Memory (DRAM), can be added by the user who requires additional storage. A popular vehicle for memory upgrades which has become a standard is a memory card termed a Single Inline Memory Module (SIMM). There are both single density and dual density SIMMs. Dual density SIMMs have twice the memory capacity of single density SIMMs.

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Stacking Single Inline Memory Module Card

      Described is a technique for increasing the memory storage of a
computer system by stacking memory cards.  Personal computers have
the feature that memory, typically Dynamic Random Access Memory
(DRAM), can be added by the user who requires additional storage.  A
popular vehicle for memory upgrades which has become a standard is a
memory card termed a Single Inline Memory Module (SIMM).  There are
both single density and dual density SIMMs.  Dual density SIMMs have
twice the memory capacity of single density SIMMs.

      Single density SIMMs generally have the memory chips attached
to one side of the memory card.  Dual density SIMMs have the chips
attached to both sides of the card.  Thus for a user to upgrade from
a single density to a dual density SIMM, the single density SIMM must
be removed and the dual density SIMM put in its place.  This is
costly and cumbersome.

      Fig. 1a shows a single density SIMM.  There are 9 memory
modules plus decoupling capacitors on one side of a circuit card.
For
example, a standard 72 bin, 36 bit SIMM memory card might have 9
modules
providing 4 bits each.  This card plugs into a standard connector.

      Fig. 1b shows the same memory card, but with all signals going
to the bottom edge contacts also connected to a card edge connector
located at the opposite edge of the card.  This connector is designed
to accept the card of Fig. 1a.  An AMP Micro-Edge SIMM ver...