Min RK

While we work this out, you can disable the behavior in your `ipython_config.py` to restore the 5.x behavior (aadded in #752): ```python # ipython_config.py c.IPKernelApp.capture_fd_output = False ```

There's not an API to turn it on and off, but looking at the code, this snippet will disable it permanently at runtime: ```python for std in (sys.stdout, sys.stderr): if...

My mistake, that only stops reading the pipe, it doesn't restore the original FD. This should do it: ```python import os import sys for std, __std__ in [ (sys.stdout, sys.__stdout__),...

From the [TextIO docs](https://docs.python.org/3/library/io.html#io.TextIOBase.buffer): > \[buffer\] is not part of the TextIOBase API and may not exist in some implementations. So it is not guaranteed to be defined, and should...

Yes, it should specify that the feature is only for posix systems. The approach to output capture doesn't work on Windows yet.

Missed the boat for 4.0 on this one, but I still think it's the right move in the long run.

@dsblank how do you use those kernels in parallel? Are you using ipyparallel at all? I mainly mean to remove the native-serialization stuff (data-pub, apply), not anything else, which shouldn't...

@dsblank I've implemented most of what I intended in ipython/ipyparallel#61. I don't understand enough about how your use of parallel in metakernel works, so I don't know how to tell...

@dsblank thanks, that still works after the above PR. Since it looks like you are sitting on top of the existing IPython engines and clients, moving the implementation shouldn't have...

Jupyter assumes UTF-8 in a number of places (the message protocol and ipynb file format, at least), so I'd support trying this. Not 100% sure, though, because as you said,...