Continuing PDP11 saga

From: Tom Leffingwell <tom_at_sba.miami.edu>
Date: Wed Jan 9 19:54:00 2002

On Thu, 10 Jan 2002, Pete Turnbull wrote:

> It will be converted. When the CPU is running a program, it only uses
> 16-bit addresses in the program. The MMU treats anything above 160000 as
> an access to the I/O page, and remaps it.

        Besides being able to map memory up to 2MW, is there any advantage
to being 22-bit over 18-bit?

        Also, can you think of any cheaply available Q-bus module that I
could set the address of to match the ADV11? I called 3 surplus places,
all of whom wanted $750 - $1,000 for their ADV11's! I talked one guy down
to $350 for one with a bad A-D converter, but was still addressable.
That's still a lot, especially for a broken board.

Thanks,

Tom
Received on Wed Jan 09 2002 - 19:54:00 GMT