[TUHS] Re: Porting Unix v6 to i386

[Johnny Billquist]

On Thu, 31 Jan 2002, P.A.Osborne wrote:

> On Wed, Jan 30, 2002 at 08:50:31PM +0100, Johnny Billquist wrote:
> > On Wednesday 30 January 2002 10:18, P.A.Osborne wrote:
> > > Having had a rummage and a chat with acolleague here at
> > > UKC - it seems that V6 will be easier than V7,  partially because
> > > of the Lions commentary - but mainly because 286 protected mode
> > > gives a very similar handling on memory management as the PDP did.
> > 
> > What a silly argument. 
> > V6 and V7 both run on the PDP-11, so the memory
> > management hardware used by them both are the same.
> 
> Having looked through the source of v6 and v7  the comments are shall
> we say minimalistic to people who are not as familiar with the PDP 
> architecture as say Ritchie and Thompson - ie ME!   Hence the Lions
> commentary makes life a darn site easier.
> 
> I am not disagreeing with the second point you have made.   However the
> point is that V7 is a development on from V6 and the memory management 
> is more complex and thus requires more work.

I thought I only made one point, and that was that the argument for V6
being easier to port because "286 protected mode gives a very similar
handling on memory management as the PDP did".

Since V6 and V7 both run on the PDP-11 it can absolutely not be an
argument for preferring V6 to V7.

Thus I think it is a silly argument.

The rest is purely speculative on my behalf, and I really don't want to
debate wether V6 or V7 would be better to port.
I have a proper PDP-11 at home, and in addition, I run RSX, not Unix on
it. :-)

	Johnny

Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt at update.uu.se           ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol