PDP-11 addressing question and a model round-up

[Vintage Computer Festival]

On Mon, 14 Feb 2005, Paul Koning wrote:

> With MMU enabled, each 4 kW chunk of program address space is mapped
> to a physical address of your choice (possibly two separate ones, in
> MMUs that support separate instruction and data space maps).  In that
> case, I/O space might not be accessible.  For user mode programs, it
> normally would not be.  The kernel would have to have it mapped, of
> course.  In principle you could map I/O space to any of the 8 virtual
> address blocks; in practice, I think it was always mapped to the top
> block, matching the default mapping.

What a sweet architecture!

-- 

Sellam Ismail                                        Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger                http://www.vintage.org

[ Old computing resources for business || Buy/Sell/Trade Vintage Computers   ]
[ and academia at www.VintageTech.com  || at http://marketplace.vintage.org  ]