Windows for Heterogeneous Environments
We have broken away from the tyranny of the mainframe. Ever since the image
of liberation offered by the video announcing the Macintosh, a homage to Orwell’s
1984, we have endowed the user with evermore powerful, personal computers. Occasionally
a special tool emerges, like the Palm Pilot, which provides personal information
management services (PIM). Of course the handheld PIM is being pushed to do
more—becoming an MP3 player, a camera, a phone, etc. But the exception
proves the rule.
Windows Server or
|Connected to a mainframe (or in today's terminology
a central server)
||Connected to a server
||Networked to a server
||Usually networked to a server
|Programs originate & execute on the server
||Programs originate & execute on server; graphics
execute on desktop
||Programs originate on server & execute on
desktop or server
||Programs usually originate & execute on desktop,
but can originate or execute on server
Based on: http://www.vecmar.com/thin_client/thin-client-definitions.htm/
Cost, flexibility, complexity, and support costs increase
With independence has come a fair share of problems. We’re finding PC
prices dropping only slightly while capacity, capability, and complexity increases
exponentially. This shortens the lifespan of PCs. Most of us are replacing desktop
systems every three to four years. Recall that in 1999 Intel introduced the
500Mhz Pentium III processor, NVIDIA released the first graphical processing
unit (GPU), and the IEEE published the 802.11b wireless protocol. If you’re
not replacing your 1999 workhorse PC (see sidebar), your students and faculty
are not being served.
Yet you’re still reeling with the cost of support. The complexity of
today’s computer classrooms and labs is driving up the costs of integration
testing, configuration, and installation. Is there no end to this?
If you prize flexibility then there is no alternative but to provide the environment
that is able to support it. It’s costly, but you can run the software
you want, configured how you want it. However, if you can find significant areas
where standardization is a positive attribute, then deployment of “thin
client” computers may work for you.
What’s a Thin Client?
A thin-client computer is stripped down to the basics. It has a network card,
processor, video card, and some local memory. The processing is done on the
server. Thin clients are built with small, single-chip designs that reduce power
consumption, maximize Internet compatibility, and present a simplified, controlled
environment for more tractable software integration.
On a thin client all applications actually run on a shared server or group
of servers, and are not executed by the client desktop. The client is responsible
for managing the screen, keyboard, and mouse information, passed to it by the
server, nothing else. Instead, the application server must have software installed
on it to manage multiple application sessions corresponding to the sessions
users are running.
Centralized applications and processing dramatically reduces the need for
hands-on maintenance. Upgrades and profiles are done on the server and automatically
deployed to every location with a client connection not by transferring the
new upgrades down each client, but enabling all the clients to leverage the
server’s upgrade and profiles. The need to touch the installed base of
machines is radically reduced. Of course, there are application deployment tools
that push out software from applications servers to connected PCs. But the simplicity
of the thin client approach makes it unnecessary to push out applications.
Remote Desktops vs. Remote Applications
Running Windows on the server simplifies things considerably. But you still
have a choice to make. Are you going to run a full Windows desktop or do you
want to run just the applications that matter to you and nothing more? A thin
client running a virtual desktop is both the simplest but also least flexible
environment. Running applications from a client extends your options since the
client can itself be something other than a PC. Why would you do that? One way
to break the tyranny of three-year equipment renewal cycles is to extend them.
But older PCs don’t run today’s applications. Then again, an older
PC acting as a client isn’t running the application, so it lives to work
for another day.
Shades of the Mainframe
If this looks familiar, it is. The mainframe has been reborn in server clothing.
To run this kind of environment you need the Microsoft Windows 2000 or 2003
application server software at a minimum. Microsoft Windows Server is the foundation
for all these Windows thin client options. The limitations of Terminal Services
on Windows 2000 Server made it suitable for only the smaller environments where
users are accessing full remote desktops. With Windows Server 2003, it’s
a more complicated decision.
After having taken the first steps, Microsoft did very little for a long time,
leaving creative third parties to develop thin client functionality. In stepped
Citrix, Tarantella, and others to provide services, management, and scalability.
The boys and girls in Redmond may have been preoccupied but they have returned
with studied determination to build a much improved product.
When D'es Thin Client Terminal Services Make Sense?
Thin Clients may be right for you if any of the following are true:
· you are using a limited set of standard MS applications;
· you are not currently running an enterprise-wide managed Windows environment;
· your enterprise is very distributed, with many WAN links;
· your network needs upgrading;
· you have a significant number of client devices nearing replacement.
Figuring out the cost effectiveness of a thin client is no small task. Various
vendors have so-called “assessment calculators” to help you categorize
your expenses and infrastructure investments (for example, see the Application
Computing Environment (ACE) Cost Analyzer by Citrix at www.acecostanalyzer.com/).
While the above conditions may tilt the calculation toward the thin client
direction, probably the two most important factors that make thin clients or
terminal application environments attractive are: (1) having a significant number
of PCs used to run a restricted set of applications, such as MS Office and a
few standard Windows programs; (2) having a mixture of clients who need to run
critical Windows applications. Either of these two settings may lead you towards
at least a small Windows Terminal Services implementation. After that, the ability
to be sure a program will run on a variety of client machines after being set
up once starts to make you wonder where else it might fit into your enterprise infrastructure.