On TechRepublic: Linux desktops have tanked: Get over it
BNET Business Network:
BNET
TechRepublic
ZDNet
TalkBack 2 of 2:
« Previous
It's not optically based - it uses electrical resistance
Phase-change memory doesn't use optics - it reads the change in resistance to determine a "1" or a "0". Rather than relying on a photodiode and photodetector per cell - it's much simpler than the system mentioned in the article. It's basically has a programming wire that heats it up and then a read wire that determines the resistance. If the programming wire heats the cell and then abruptly shuts off, the flash "freeze" of the cell gives a different resistance value than if the programming wire gradually turns down the heat.

See: http://en.wikipedia.org/wiki/Phase-change_memory

[quoting from the Wikipedia link above]
The crystalline and amorphous states of chalcogenide glass have dramatically different electrical resistivity values, and this forms the basis by which data are stored. The amorphic, high resistance state is used to represent a binary 0, and the crystalline, low resistance state represents a 1. Chalcogenide is the same material utilized in re-writable optical media (such as CD-RW and DVD-RW). In those instances, the material's optical properties are manipulated, rather than its electrical resistivity, as chalcogenide's refractive index also changes with the state of the material.
Posted by: pmahoney   Posted on: 04/18/07 You are currently: a Guest | Members login | Terms of Use
Reply to Story Reply to Message

Alert moderator to an offensive message

Subscribe to this discussion via Email or RSS

Not CD-ROM. That's Read Only.  gordon@... | 04/17/07
It's not optically based - it uses electrical resistance  pmahoney | 04/18/07

What do you think?

SponsoredWhite Papers, Webcasts, and Downloads

advertisement

SmartPlanet

Click Here