[IPython-dev] Kernel-client communication

Hans Meine hans_meine at gmx.net
Fri Sep 3 05:18:38 EDT 2010

Am Freitag 03 September 2010, 10:30:29 schrieb Almar Klein:
> * You plan on keeping history in the kernel. In this case I think this is
> the task of the client. Otherwise you'd get your own history mixed with
> that of someone else using that kernel? History is, I think, a feature of
> the client to help the programmer. I see no use for storing it at the
> kernel.

That's an interesting issue.  Some more random thoughts:

- If you decide to connect to an existing session (from home or the bar via 
your smartphone) to check something and/or issue a command, it is very useful 
to reuse your existing history -> should be in the kernel

- If you are using only one frontend/client, it does not matter anyhow, only..

- If the kernel is busy, it could still be useful to browse through the 
history to compose the next command(s) -> should be in the client?

- In the multiple GUI/observer scenario, I think it would not hurt to share 
the history with the observer either -> could be in the kernel

Is there any other reason to have the history in the client, Almar?

Otherwise, I's say of course it's a feature of the client, but obviously there 
are good reasons (in particular when detaching/attaching) to have the history 
be stored in the kernel.  Maybe it needs to be duplicated/synchronized to 
support situations where the kernel cannot respond, though.


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