11 Sep
2015
11 Sep
'15
8:03 a.m.
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.
paul