On Tue, 30 Jan 2018, Paul Ruizendaal wrote:

> “One widely distributed (though undocumented) solution to this hardware 
> limit on the model 40 was a version of Unix by Robert Sidebotham, 
> Faculty of Environmental Design, University of Calgary. His solution was 
> to move the I/O buffers out of kernel space.”

I wonder if that inspired the AUSAM buffer management?  The current buffer 
header was "b" (like "u") which got mapped by KISA5.

For the first time I was able to avoid our 11/40 deadlocking; I can't 
remember all the devices that were on it, but there were a *lot* 
(including the printer driver etc which used the buffer pool, not the 
character queue).

-- 
Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."