I believe there was,

by mrmacfixit Moderator - 4/8/13 4:52 PM

In Reply to: Link, comment. by R. Proffitt Moderator

you and I had this conversation many years ago.
I don't remember the exact details but it was essentially about a series of Macs that could not address, fully, any hard drive greater than 120GB

Anything larger than that would be presented as a 124GB drive.

Just remembered, it was Logical Block Addressing that was the problem and from what I can find, all the early iMacs could not address larger than 120GB (or thereabouts)