IBM's Phase Change Memory stores three bits per cell
IBM has developed a prototype PCM - Phase Change Memomory - chip capable of storing three different values per cell instead of the normal 2. They also developed a new control mechanism capable of dealing with drift (which they say the new type of PCM chip does not experience).
I, for one, welcome our new ternary overlords.
I, for one, welcome our new ternary overlords.
So this has nothing to do with ternary data.
The comparison with 2-bits comes probably from the fact that previously it was only possible to store 2-bits per cell in PCM (phase change memory).
For example with flash memory there is SLC where each cell stores 1 bit and MLC where more bits are stored, in particular they also have TLC with 3-bits per cell. MLC for flash makes the storage denser and cheaper, but also increases wear.