Re: Why VAX Was the Ultimate CISC and Not RISC

On Mon, 3 Mar 2025 16:34:35 +0100, Terje Mathisen wrote:

... while the guy who hired me kept his belowed DEC Rainbow which he
felt had the better architecture:

I only had a brief exposure to them, but I think they were beautiful
machines, too.

For one thing they did not break Intel's rules about where to place the
interrupt vectors. In hindsight this was a bad decision since 100%
compatibility with Microsoft Flight Simulator was an absolute
requirement at the time.

This is why I refer to “Microsoft-compatible”, rather than “IBM-
compatible”, PCs. Because it was Microsoft that very quickly took over the
mantle of arbiter of “compatibility” from IBM.

Anton Ertl wrote:

>
They did not succeed.  Maybe that's the decisive difference from HP:
They did succeed in the PC market.

Bell mentions that: DEC tried to set a standard (a reasonable thing to try
in 1982), and failed. They should have quickly pivoted to embracing the
actual standard that won, but they did not.