PDP-11 architecture Was: internet blocking problem ?

Johnny Billquist bqt at update.uu.se
Fri Sep 11 09:39:44 CDT 2015


On 2015-09-11 16:36, Noel Chiappa wrote:
>      > From: Jon Elson elson
>
>      > I actually LIKED the PDP-11 architecture quite a LOT, but the limited
>      > memory was a big killer.
>
> The good thing about the PDP-11 was the 16-bit word size. (It resulted in
> what's probably the most elegant architecture, in bang/buck terms, of all
> time.) The bad thing about the PDP-11 was the 16-bit word size. (For the
> reason you point out.)

WHile I agree that the PDP-11 is a wonderful architecture, it really is 
a few bits short of perfect, both for addressing, and for opcode allocation.

The is obvious when you look at the EIS and FPP extensions, which could 
not retain the general instruction layout format because of a lack of bits.

	Johnny



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