On 2 Aug 2012, at 06:52, Roger Bishop Jones wrote:

> On Thursday 02 Aug 2012 00:33, you wrote:
>> On 01/08/12 14:35, Roger Bishop Jones wrote:
>>> The real challenge (for me at least) is to get xpp
>>> and/or emacs to run in the cloud with a display here
>>> on earth, I don't have much clue how to do that.
>> 
>> I've been thinking about this.  To me, it seems
>> conceptually wrong to be running Xpp remotely.

Well actually, it is exactly what was expected to happen in the original X 
Windows concept - run applications (called X clients, because they are clients 
of the local GUI services) remotely and have the GUI appear on local machine 
(running an X server, because it supplies GUI services to the remote 
applications). In that model, the client connects to the server using the 
standard network protocols for client-server connection. But this model is fine 
on a well-managed intranet but raises a lot of security issues in the wild 
world of the Internet.

> 
> Mm.
> I don't know about "conceptually", but there is a question 
> here about what problem I am trying to solve.

Exactly.  This is the old debate about thick clients v. fat client. Both have 
there merits, but it depends what your are trying to achieve.

> 
>> Would it
>> not make more sense to run a local (earth-based) Xpp
>> whose journal window contains a remote ProofPower shell
>> (up in the cloud) via e.g. ssh?

> 
> If I were just interested in running ProofPower in the cloud 
> then that would be correct. And this something that one 
> might like to investigate.

Unfortunately with things stand, Phil's fat clients would hold the user's 
source files locally while the ProofPower theory database is held remotely. 
That makes sense if you just want the server to offer a stateless service 
whereby you uploaded your specs and proofs each time, It would also make sense 
for collaborative work, but to make that really work, you would want to adapt 
ProofPower to have a model supporting multiple concurrent users accessing a 
shared database.
> I don't see how that would make sense.
> 
> I am really looking for a complete X11 framebuffer (is that 
> what they call it?)
> which  is is remote, so that not only 
> Xpp but also other tools like emacs run remotely.

X clients like xpp and emacs always run "remotely" in that sense. In the X 
jargon, what you are wanting to do is run the X server remotely as well as if 
it were connected to a virtual monitor and keyboard in the cloud and using 
something like VNC to connect a window on your monitor and your keyboard to 
those. I have used a product called Citrix that is along the same lines of VNC. 

> There does seem to be software which does that (e.g. using 
> "VNC"), but the documentation seems to assume you know a lot 
> more than I do.
The above is about as much as I know.

> Alternatively X11 forwarding over SSH looks like it allows 
> any applications you open on the remote host to operate 
> windows on the local machine (but this is not supposed to 
> perform very well or to provide robust connections).

That is what X11 forwarding in SSH is intended to do and it has worked fine for 
me in the past. But that has mainly been within a LAN.

>  These 
> are the two scenarios I am investigating at the moment, 
> along with a third which I'm not sure where it fits but which 
> might be what amazon best supports (because I can see it in 
> their yum depositories. which seem light on X11 package 
> groups) viz. Xephyr.

I think Xephyr is a kind of proxy X server that gets to the GUI by acting as an 
X client to another X server. I don't see how it gets round the problem of 
establishing an X connection from the remote machine to the local one. I.e., 
you'd still have to use something like ssh X forwarding. However, there may 
well be more to it than that.

Regards,

Rob.


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