On Mar 9, 2015, at 5:13 PM, Hans Hagen wrote:

i uploaded a new beta ... works at luigi's end (actually we tested that 
previous time too but the issue is only triggered in docs that use 
positions and tuc files remember that)

Hans

Now with current version: 2015.03.09 22:02 and 
\starttext
\input knuth
\stoptext

I get:

open source     > 3 > 4 > knuth.tex
open source     > 4 > 5 > knuth.tex
open source     > 5 > 6 > knuth.tex
...
open source     > 125 > 126 > knuth.tex
open source     > 126 > 127 > knuth.tex

tex error       > error on line 2 in file knuth.tex: ! TeX capacity exceeded, sorry [text input levels=127]

l.2 \input knuth
              

1     \starttext
2 >>  \input knuth
3     \stoptext
4     

If you really absolutely need more capacity,
you can ask a wizard to enlarge me.



No problem with \input ward \input zapf \input lorem