Replies to various threads

From: Philip.Belben_at_powertech.co.uk <(Philip.Belben_at_powertech.co.uk)>
Date: Thu Apr 23 08:14:22 1998

I haven't got time to type loads of messages. These are in a roughly
random order.

First, thanks to Pete, Allison and others for explaining the PDP11-23
stuff. I stand corrected, I suppose.

Tony Duell wrote:

> BTW, does anyone know the position on reverse-engineered schematics? Who
> owns the copyright on those? The original company, the person/company
> who drew them out, what? Or are they just plain illegal (I doubt the
> latter, as I've seen them advertised as such for devices where original
> manufacturer's manuals are not available).

AFAIK, you both do. You own the copyright in the diagram you've drawn
out, and the original designer/manufacturer owns the copyright in the
circuit it represents. So if I want to copy it I need permission both
from you and from the designer. (It's like if I want to photocopy a
book I need permission from both the author and the publisher.)

Allison Parent wrote:

> Competing against the mostly 16bit 8088/6 and the 286 the PDP11 was out
> front. To match a 16bit cpu against a 32bitter... you must be inhaling!

A long running discussion. Allison, I don't understand how you can say
that the PDP11, with its very simple instruction set, is _more_ CISC
than (say) the 80286, with which you compare it here. To my mind the
only really CISC feature of the PDP11 is the MARK instruction. I fear
we may be talking at cross purposes, and may mean different things by
RISC and CISC - could you give some specific examples, please?

For those who think a souped up PDP11 could be a pentium killer, bear in
mind that there was a 32 bit PDP11. I don't mean the VAX, and I don't
mean the PDP11-68: I mean the Motorola 68000. AFAICT the two
architectures are very, very similar. Is it a Pentium killer? The
68070 might have been but it's rather faded away now...

Just my half groat's worth again!

(Yes, Tony, half a groat == tuppence == two pence == two pennies = (in
some sense) $0.02, which seems to be the value most people set on their
opinions here. About right in most cases (no offence intended))

Philip.
Received on Thu Apr 23 1998 - 08:14:22 BST