Phase Change materials to data?

As we know, Phase Change Memory is composed of glass like materials called "chalcogenides" and are classified as phase change materials or PCM. So the question is, how does switching from one phase to another store data?

Well first lets analyze the basic concept of data.

http://static.ddmcdn.com/gif/bytes-ch.jpg

• Data, is a collection of  values, measurements, or facts
• Data is not information until manipulated to a meaningful context
• Data is represented as bits (zeroes or ones)
• every group of 8-bits creates a byte- which then is further grouped into KiloBytes (1024 bytes) and MegaBytes (1024 KiloBytes) etc.

An common example of a typical device that stores data, are our flash drives.

Now how does a chalcogenide turn from physical object to a data unit. Well, in each cell of a memory chip chalcogenide are placed between two electrodes. One of which melts the chalcogenide creating a highly resistive material. At this point, since the material is highly resistive to electricity, when an electrical impulse is applied the resistive material.
at this point the cell would represent a binary digit of 0 (bit value of 0) and when this melted material is cooled and crystallized it would represent the binary digit of 1 (bit value of 1).

hence when a memory chip is collecting data, all it really needs to do is either is melt or crystallize the material to represent the data.


Web Links:
Altered States - Economist
New Memory Chip- CIO