Dual In-Line Memory Module

Dual In-line Memory Module

   <storage> Small circuit boards carrying memory {integrated
   circuits}, with signal and power pins on both sides of the
   board, in contrast to {single-in-line memory modules} (SIMM).

   The individual gold or lead connectors (pins) on SIMMs,
   although they are on both sides of the chip, are connected to
   the same memory chip, while on a DIMM, the connections on each
   side of the module connect to different chips.  This allows
   for a wider data path, as more modules can be accessed at
   once.  DIMM pins are arranged in a zigzag design to allow PCB
   tracks to pass between them.

   The 8-byte DIMM format with dual-sided contacts can
   accommodate 4- and 16-megabit {dynamic RAM} chips, and is
   predicted to handle 64- and 256-Mbit devices.  The 8-byte DIMM
   will hold up to 32 megabytes of memory using 16-Mbit DRAMs,
   but with the 256-Mbit future-generation DRAM, it will be able
   to hold a 64-Mx64 configuration.  Another variation, the
   72-pin {SO-DIMM}, is designed to connect directly to 32 bit
   data buses, and is intended for use in memory-expansion
   applications in {notebook computers}.

   A Dual in-line memory module (DIMM), as opposed to SIMMs (used
   by the majority of the PC industry) allows for a 128-bit data
   path by interleaving memory on alternating memory access
   cycles.  SIMMs on the other hand, have a 64-bit data path.
   Suppliers are unanimous in their belief that the DIMM will
   eventually replace the SIMM as the market's preferred memory
   module.

   (1996-01-28)