Definition

phase-change memory (PCM)

Part of the Computing fundamentals glossary:

Phase-change memory (PCM) is a form of computer RAM (random-access memory) that stores data by altering the state of the matter from which the device is fabricated. The structure of the material can change rapidly back and forth between amorphous and crystalline on a microscopic scale. In the amorphous or disordered phase, the material has high electrical resistance ; in the crystalline or ordered phase, its resistance is reduced. This allows electrical current s to be switched on and off, representing digital high and low states. Working prototype s of PCM chips have been tested by IBM, Infineon, Samsung, Macronix and others.

According to its proponents, PCM technology has the potential to provide inexpensive, high-speed, high-density, high-volume nonvolatile storage on an unprecedented scale. The physical structure is three-dimensional, maximizing the number of transistor s that can exist in a chip of fixed size. PCM is sometimes called "perfect RAM" (PRAM) because data can be overwritten without having to erase it first. This makes it possible for PCM to function many times faster than conventional flash memory while using less power. In addition, PCM chips are expected to last several times as long as currently available flash memory chips and may prove cheaper to mass-produce.

The acronym PCM also stands for pulse code modulation . The acronym PRAM also stands for parameter RAM .

This was last updated in March 2011
Posted by: Margaret Rouse

Related Terms

Definitions

  • MIS (management information systems)

    - MIS represents the most critical -- and often, most proprietary and difficult to upgrade -- applications used internally by enterprises. (SearchDataCenter.com)

  • flash storage

    - Flash storage, based on flash memory, is used for data repositories, storage systems and consumer devices, such as USB drives, smartphones and solid-state drives. Flash-based storage is faster than... (WhatIs.com)

  • statistical mean, median, mode and range

    - Calculating the mean, median, mode and range of a set of numbers allows you to track changes over time and set acceptable ranges and variance. Here's how to find your data's mean, median, mode or r... (SearchDataCenter.com)

Glossaries

  • Computing fundamentals

    - Terms related to computer fundamentals, including computer hardware definitions and words and phrases about software, operating systems, peripherals and troubleshooting.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question About phase-change memory (PCM)Powered by ITKnowledgeExchange.com

Get answers from your peers on your most technical challenges

Tech TalkComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.