Crossbar or Crosspoint?

Computing Crossbar SwitchThe Memory Guy has recently run across a point of confusion between two very similar terms: Crossbar and Crosspoint.

A crosspoint memory is a memory where a bit cell resides at every intersection of a wordline and a bitline.  It’s the smallest way you can make a memory cell.  Think of the wordlines and bitlines as the wires in a window screen.  If there’s a bit everywhere they cross, then it’s a crosspoint memory.

In most cases a crossbar is a communication path in a computing system.  (Of course, there are exceptions, the main one being a company, Crossbar Inc., that is developing a crosspoint memory technology!) A crossbar communication path is topographically similar to a crosspoint, but its function is to connect a number of memory arrays to a number of processors.  Visualize a vertical column of memory arrays named A, B, C… and a horizontal row of processors named 1, 2, 3… as is illustrated in this post’s graphic.  The crossbar can connect Processor 1 to Memory A, or to any other memory that is not already connected to another processor.  These connections are represented by the circles in the diagram.  You can see that this is an efficient way to allow processors to share a memory space to achieve very high speed inter-processor communications.

Crossbars are quite likely to Continue reading

Crossbar’s Radical New Memory Technology

Cross Section of the Crossbar Memory CellCrossbar, Inc. has come out of stealth mode with a fascinating new alternative memory technology.  Furthermore, the company says that a working memory array has been produced at a commercial fab.

Crossbar says that the technology can put a terabyte onto a single chip.  The company has already measured filaments as thin as 6nm, and is confident that it can be shrunk further and that it will support multilevel cells.

Crossbar’s device is a silver filament ReRAM with a difference.  For one, the silver filaments are in standard silicon dioxide, probably the most Continue reading


Jim Handy Objective Analysis Memory Market Research +1 (408) 356-2549 Jim.Handy (at)

Translate to:

Website Translation GTS Translation