PDP-11 = Pentium Killer?

From: Allison J Parent <allisonp_at_world.std.com>
Date: Thu Apr 23 11:05:26 1998

<FWIW, it's been my experience that on problems small enough to be tackle
<by the J-11, an 18MHz J-11 eats the VAX-11/780 for lunch.

The PDP-11 is no slouch. I've used the T-11 part for some things and
even using the pokey 7.5mhz clock some tasks are faster than most
anything contemporary to it like the z80/8mhz even though the numbers
say slower. It's that CISC with superior addressing modes that put it
out ahead.

I've found the same but it's task dependant and also the 780 is always
doing more than the J-11 due to OS. I did get a chance to try that
once and the 780 was running nothing more than the usual background
tasks and it was close but then both are about 1mips. Same was true in
1978 when the 11/70 was put up against the 11/780. The 2vup and faster
VAXen made it a no contest in favor of the VAX though. As soon as the
task exceeds 64k or the user/task load gets up there the differences
start to stretch out with the vax ahead. A faster PDP-11 will always
have that disadvantage.


Allison
Received on Thu Apr 23 1998 - 11:05:26 BST