[dom0]

> Slight aside, there are a lot of reasons that Itanium failed, but certainly one of them was lack of backwards compatibility.

Itanium did not aim at the x86 market. The x86 translation layer was retrospectively seen as a mistake as well, because it wasn't relevant, but required transistors that limited the design's performance overall, which was relevant.

[cwyers]

> Itanium did not aim at the x86 market.

Maybe not. But x86 certainly took over the market Itanium was aiming for.

[nine_k]

x86 did not. x64 did.

[cwyers]

All 16 and 32 bit x86 code is valid on x64. It's an extension, not a new ISA.

[geezerjay]

You got it all backwards. AMD64 is a complete revamp which happens to support x86 in its legacy mode.

Server people care for 64-bit address spaces, and that's a feature introduced by AMD64 which is not available in x86.