Re: [seul-edu] thin clients using Linux in the classroom?

[owner-seul-edu@seul.org (Nobody)]

Disclaimer: I'm not only "certifiable" as many of you know, but I'm 
also "certified" as a Citrix administrator. At least, assuming my 
certification hasn't lapsed yet - It's been a little over 3 years, 
and I never did pursue their higher-level certifications when they 
came out about 2 years ago.

> Citrix bandwidth is reportedly much lower than Xterminal, such as 
> for
> remote applications over dial-up to "digital divide" students at 
> home
> on slow computers excessed from the school, running only the Citrix
> free client off a floppy.
> 
True - with a low-latency connection, even a 9600 bps modem is 
somewhat tolerable for most tasks with Citrix.

>   Citrix server is also available for
> Solaris, which may be able to run some Linus apps. For discussion of
> X (including LBX - low bandwidth X) versus Citrix see: 
> http://mail.gnome.org/archives/gnome-devel-list/2002-January/msg00127.html
> 
However, Citrix has discontinued Unix support (they also ran off 
another Unix, AIX IIRC?). They said they weren't making any money 
off of it because most places where they wanted an X app, they 
already had an X server on the client and plenty of bandwidth 
between them. They did have a small niche for remote offices and 
home workers, but not enough to justify spending more on it.

> However, Citrix is less flexible than Xterminal - only run apps on
> the server, compared to either server or client with X. Citrix can 
> be
> expensive(watch licensing terms for server and apps), and hard to 
> set
> up.
> 
Bzzzt. ...but we thank you for playing and have some nice parting 
gifts for you. :-)

They call it "published applications". Microsoft's Terminal Services 
(available as Windows NT 4.0 Terminal Server Edition (TSE) or 
included as "terminal services" under Windows 2000) does not have 
this ability - it's all or nothing. Citrix even has a mode for Win32 
and Mac (again, drawing from memory that hasn't been exercised in a 
couple of years) called "seamless windows", that allows you to cut, 
copy, paste, and save from a published application to your local PC, 
so you could be running Photoshop locally (you *wouldn't* want to do 
this over a Citrix session), but when you click on your MS Word 
icon, it would actually launch it on the Citrix server, though it 
would look to you like it was running locally.

As far as difficult to setup, not really. The biggest pain is 
dealing with Microsoft licensing (<mockingly>imagine 
that!</mockingly>). You've got to have a server client access 
license (CAL) (~$10 academic), a terminal server CAL (TSCAL) unless 
you have the same version or higher windows on your desktop (i.e., 
TSE doesn't require a TSCAL if you're running NT4 Workstation, Win2k 
Pro, or WinXP, Win2k with terminal services doesn't require a TSCAL 
if you're running Win2k pro or WinXP, but does if you're running NT 
or 9x, Mac, anything else) (~$40 academic). This much will allow you 
to run the MS client (which only works on WfW3.11 or better), or as 
somebody else here mentioned rdesktop.org - full desktop only. The 
Citrix add-on is about $200/seat retail (the bidding process can 
usually get them to you significantly cheaper). They've just changed 
their model from concurrent (in version 1.8) to per seat (in version 
XP).

The actual software installation is a breeze - much easier than X, 
in my experience. Expensive, yes - difficult, no.

>   Inside a school building, with today's high speed LANs,
> bandwidth may be less important. Also check out multi-OS linking VNC
> 3.3.4 -- 
> http://www.realvnc.com/pipermail/vnc-announce/2002/000037.html  --
> with:
> 
>   * vastly improved low-bandwidth performance
>   * automatic protocol selection based on line speed
>   * efficient multi-viewer ("classroom") support on the Windows
> server
> 
We also use VNC, but I use it for a completely different function 
altogether. I use it for remote assistance. Somebody in one of our 
elementary schools 9 miles away can call with a problem, and I can 
take over their PC and explain what I'm doing whilst fixing the 
problem - saves driving time and helps them figure out their own 
answers at the same time. I haven't seen the "multi-viewer" support 
though - I may have to investigate.