1GHz PDP-11 (Re: Prints for an 11/70)

From: Jerome Fine <jhfine_at_idirect.com>
Date: Fri Dec 14 09:06:48 2001

>no wrote:

> Pricey beasts, those bridges. Looked into that a few years ago when
> my company was thinking of replacing the 11/45's with the Osprey
> board. Unibus bridges were about $2500 each.
> -nick

Jerome Fine replies:

The price of the bridges has not been reduced, but the Osprey was a
relatively expensive solution - much more than the cost of the bridge
if I remember correctly. Also, limited in CPU power to the hardware
that is used. A less expensive solution - the difference effectively
makes the cost of the bridge zero or even negative - is Ersatz-11
Obviously you require the commercial version and you still run on
a PC, but as the speed of the PC increases (at increased cost of
course), so does Ersatz-11. Not so with the Osprey hardware.
And I seem to remember that the cost without the bridge was twice
the cost of even the first the Ersatz-11 license.

I am not saying that Osprey is a bad solution. When I first saw a
system that used the J11 chip (so that the speed was about identical
to an 11/93 - maybe a bit faster since the memory may have been
integrated more efficiently), I was very impressed. It was probably
about 5 or 6 years ago - well before the commercial version of
Ersatz-11 which initially arrived without an adapter capability.
Later, the Osprey solution started to use their own CPU to replace
the J11 - had to eventually since DEC cut off supply of the J11 chips.
But the Osprey is still much slower than Ersatz-11 is able to achieve
now on a Pentium IV. I think that on the fastest Pentium IV, Ersatz-11
is now able to execute PDP-11 instructions more quickly than any
other emulator and/or hardware. And since the original trial version
of Ersatz-11 is probably close to 10 years old, maybe I am not
even off topic.

Does you company still have the PDP-11/45 systems?

Sincerely yours,

Jerome Fine
Received on Fri Dec 14 2001 - 09:06:48 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:33:39 BST