> On Sep 11, 2015, at 10:49 AM, Warner Losh <i...@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.
paul
