PDP-11 architecture Was: internet blocking problem ?

Paul Koning paulkoning at comcast.net
Fri Sep 11 10:03:55 CDT 2015

> On Sep 11, 2015, at 10:49 AM, Warner Losh <imp at bsdimp.com> wrote:
> ...
> I loved the PDP-11 architecture, until I wanted to run programs on it that
> relied on the overlay manager and the overlays got to be 8 or 9 deep. Then
> it was... painful.

Perhaps the program was too large.  But it may just be that the overlay structure was not right.  Overlays involve significant overhead, and it's well known that the flexibility of TKB can cost a lot.  (TKB itself is an example of that, which is why there was a button with the text "TKB forever... and ever... and ever...".)

For efficient overlays, RT-11 with Link tends to be better.  It's less flexible but that reduced flexibility enforces more care in overlay design, and the implementation is a whole lot faster.


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