Re: Advice needed on developing app for linux

From: Elp (rockfamily_at_hotmail.com)
Date: 08/12/04 

Date: 12 Aug 2004 16:36:14 GMT

Graeme Hinchliffe wrote:
> Yes I thought there would have to be more to it than just a desktop.
> But I still fail to see the advantage. If you can run rdesktop to
> the remote machine running your component setup control software why
> would you need more than just that? You can give them all the links
> they would need on the desktop to the various apps, the same applies
> with X, as it is designed to run accross a network.

Your suggestion is interesting is this is actually what we've tried to do at
the very beginning of this project. The result of this experimentation was:

- it works this way but...

- controling access to the remote machine is far from being easy. Only one
person should be allowed to use the remote machine (and hardware connected
to it) at any given time. That's why we've put in place a booking system. If
the students have simply a remote desktop application to access the system,
restricting access to the remote machine to only authorized users *who have
booked a slot of time for this particular time and day* is difficult. Not
impossible though, i admit that.

- it's slow. Fine on a LAN but way too slow on the internet. The Flash
virtual circuit that you can see on the screenshot for example is a pain to
use through remote desktop. For the specialized application that can only
run on the remote machine, they have to do with it. But for everything else
(flash circuit, lecture video, instruments control...) it's much better to
have the front end running on the students computer so that it's fast and
comfortable.

- it's not exaclty very easy to use by the end users. Having links on the
desktop of the remote machine is fine. Or even a custom launching
application to launch everything automatically . But this is messy and i
predict that the users are going to be quickly lost with all those stuff
launched on the remote desktop. Not to mention the fact that they of course
have a choice of several experiment thay can do, each of them having their
own instructions, flash circuit, lecture video... Switching between them is
a breeze with our app (the app takes care of displaying and configuring the
proper files corresponding to the choosen experiment) but will be a pain to
do if everything is running independantly.

Our goal is to make an application that recreates in the most faithfull way
the course of a lab session. Ie, in the lab, the students have in fromt of
them all the crcuits, wires, electronic instruments, a PC connected to the
instruments with all the need software and a teacher who can help them. With
our app, they have exaclty the same things in front of them. They click on
the circuit button and they have the circuit. The same for every other
features. And all is running on their computer apart from the fact that
informations are constantly send to our servers to recreate on the real
harware what they are doing on their screen. Which means for example that
the Flash circuit is very fast and comfortable to use as it's running on
their computer and all info about the wiring they have done is only sent to
our servers when they click the "send" button (this can be fast or slow
depending on their connection speed but at least they wait only when all the
wiring has been done and doing the wiring is not a hassle).

> If it is the security aspect of having such resources open to the
> world then a VPN could most likley provide the remote student with
> the access to the University network that they need to access the
> resources they need to view, and could be used to tunnel the
> communications for the electronics software also.

I wish we could use a VPN. But unfortunately, it out of question. We don't
have one set up at the university anyway (not as far as i know). And we want
to provide a no brainer software for any student to access our lab. For
example, if somebody from new zeland or brazil wants to subscribe to our
remote course, all they have to do is download our application (a few MB),
install it on their computer, we add its username and password in our databa
se and there you go ! No configuration needed on either part. A truly global
system :-) well, not really at the moment because Windows is required.