On Tue, Jul 21, 2009 at 10:44 AM, William Stein<wst...@gmail.com> wrote:
>
> On Tue, Jul 21, 2009 at 9:39 AM, Ondrej Certik<ond...@certik.cz> wrote:
>>
>> On Tue, Jul 21, 2009 at 1:58 AM, Robert
>> Bradshaw<rober...@math.washington.edu> wrote:
>>>
>>> On Jul 20, 2009, at 9:02 PM, Ondrej Certik wrote:
>>
>>>> Well, let me say that I really like to run things on the appengine,
>>>> rather than to constantly maintain our own servers. I see no reason
>>>> why the notebook cannot run on the appengine, only the AJAX would talk
>>>> to our own server with Sage to actually evaluate the cells (and for
>>>> many people, I think appengine itself could actually be enough). I
>>>> have to think though what the best way to transfer data to the
>>>> database with worksheets is though.
>>>
>>> +1, though for Sage we rely heavily on compiled code. I wonder how
>>> much introduced latency there would be if the backend were served on
>>> a university computer, and the front end in appengine.
>>
>> I think none, it would be as fast as it is now (e.g. the browser
>> communicating directly with the engine).
>
> How is it "none", given that there are now three separate computers
> involved instead of two?  There would have to be a little extra

What I meant is that the latency in typing 1+1 into the cell and get
the output cell saying 2 should not change at all, because the
javascript in the browser sends a POST request to the Sage engine
(e.g. a web app with the url interface, just like it is now) and it
returns it back directly to the browser.

What changes is the database storage, e.g. either the javascript in
the browser, once it receives the output of the cells also sends it to
the appengine (or whenever the database is running), or the engine
sends it itself, I don't know yet which approach is better. So there
are some issues involved, like if one of those connections fail etc.
But as long as both connections are up and running, the user would not
recognize anything at all.

> latency, i.e., whatever there is between appengine and the "sage
> engine".  That said, the internet is pretty fast these days :-).  And
> the scalability of a decoupled approach like we're talking about is a
> big plus, if it works.

Right, it has to be tried to see if it works. But I think it's worthy.

>
> By the way, if you haven't already, I personally think you should
> start a mailing list, web page, trac, etc. for a separate notebook
> project, since you're already writing code.   There's already some
> confusion about where we are supposed to have this discussion -- and a
> funny mix of sage-devel and codenode doesn't seem right.

Well, I hope codenode guys could pick this up and they would be the
notebook. I unfortunately probably can't spend too much time on this,
until september. But I wanted to get this going to see which approach
to take.

I wrote the above in about 2 days (roughly), but it's only the first
90%, e.g. the cells sort of works, but the rest 10%, like tab
completion, worksheets, saving. loading, publishing, users, fixing it
so that it works 100% in all browsers..... That would take a lot more,
and I can't do it yet. But I hope it's encouraging to all of you to
learn some AJAX too till September, so that we can work on this
together. :)

There is one more thing I want to try -- pyjamas, as pointed out
above. I already played with it yesterday, and what I saw so far is
*impressive*. So my next step will be to rewrite what I did into
pyjamas (e.g. just pure python both on the server and in the browser).
If that works and I think it could, well, that would be the way to go,
since I could debug all those functions like for calculating cursor
positions etc. in Python.

Ondrej

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