Dial Up Your Applications
If you've used computers for
any time, you've probably accessed another computer remotely, either by phone or
by a network connection. In the beginning, the programs that made this
capability possible were simple terminal-emulation programs that supported basic
character displays.
Later, terminal programs let you use emulation, such as VT-100, VT-220, and
Tektronix emulation, to display some rudimentary graphics. As GUIs began to gain
market share, simple terminal programs were no longer adequate. Computer users
wanted the same slick GUI and all its amenities, whether they ran programs
locally or remotely. The UNIX community addressed this issue with the X Window
System.
In the Windows and DOS markets, programs such as pcANYWHERE let you run
native applications remotely. The programs executed on the remote machine--the
host--and the results were piped to your machine--the client. These
second-generation programs were slow and offered access to only one user at a
time.
The multi-user problem had many interesting solutions. One vendor offered a
PC full of cards that were individual computers--one computer for each user.
Multiprocessor computers are commonplace now, but then they were quite a
novelty. Specialized software gave each user access to his or her own virtual
computer. The problem was that every time a screen changed, the host computer
had to send all the information to the client computer. (Generally, the link
wasn't too fast to begin with.) All this traffic caused lengthy delays and made
the application an exercise in frustration for all but the most die-hard user.
Along Came Citrix
Citrix divided the problem into two parts: First, address the speed
concerns. If you had to wait 1.5 to 3 minutes for a screen update, this
technology's success was going to be limited. Second, reduce the cost per user.
If more users could use the same machine at the same time, companies could
amortize costs over those users.
Citrix developed a product that solved both parts of the problem: WinView
ran on OS/2 and performed reasonably well. WinView made multi-user remote access
possible at a reasonable speed, but the product wasn't really the one Citrix
wanted to build. This situation was a case of Citrix being ahead of its time.
OS/2 just didn't have the horsepower to do what Citrix had in mind.
We won't tell you that Windows NT's rapid rise and success saved Citrix.
The truth is, the Citrix technology is so good that if NT weren't available,
Citrix probably would have chosen some other platform. But in the end, NT is
exactly what Citrix was looking for.
The result of this story is WinFrame for Networks. WinFrame is not
a service that runs on NT; it's an extension to NT.
What? A proprietary version of NT? Well, sort of. When you install
WinFrame, you are installing NT. Citrix has licensed the source code from
Microsoft and extended the NT kernel to allow multiple simultaneous desktops for
concurrent users. Sounds confusing, but it really isn't.
Building on NT's strengths, such as Remote Access Service (RAS),
scaleability, symmetrical multiprocessing (SMP) support, security, and
remote-node communications, WinFrame adds concurrent multi-user event tracking,
messaging, and performance monitoring. In addition, it provides utilities for
configuration and multiple concurrent profiles. The coup de gras is the
Citrix Intelligent Console Architecture (ICA) protocol. This protocol is what
makes WinFrame faster than other remote-node software.
Installation/Configuration
Installation for WinFrame takes about the same time as installing Windows NT
Server, and the installation program is the same. Currently, WinFrame runs only
on Intel platforms. The Windows NT Magazine Lab chose a Telos
100-MHz Pentium with 64MB of RAM and a 2GB SCSI drive. A 3Com 3C589 EtherLink
III card rounded out the mix.
We didn't experience any surprises. The beta version we tested didn't add
the WinFrame icons to the Administrative Tools program group. But a quick call
to customer support gave us a workaround and a promise to fix this oversight in
the shipping product.
Next, you configure a WinStation, which is like a virtual machine. If five
concurrent users will be logged on to your WinFrame machine, you need to
configure at least five WinStations.
Configuration is straightforward. First, select the WinStation
configuration icon from the Administrative Tools group. Next, choose the
WinStation drop-down menu, and select New. Screen 1 shows a sample WinStation
dialog. You tell WinFrame what network transport protocol to use in the
Transport box, and in the Type box, you tell it what type of client computer
will communicate over this link.
Remotely Possible?
With the server taken care of, the client is next. WinFrame supports a
variety of clients: DOS, Windows 3.11, Windows 95, and Windows NT. We focused on
the NT client.
The omnipresent InstallShield program lets you install the client portion.
Insert the disk, run the setup.exe program, supply a directory path for the
executables (or take the defaults), and you're done. Then, you can open the
WinFrame Client group and click on the Remote Application Manager icon, as you
see in screen 2.
To add a new remote application, you need to know which network protocol to
use and the name of the WinFrame server. You also need to supply a valid user
ID, domain name, and password for automatic logon. If you don't, you must log on
to the WinFrame server just like any other NT server. Once you establish the
connection, you can run any program on the WinFrame server.
WinFrame's ability to save the connection as an icon on your desktop is an
especially nice touch. If you enable the automatic logon feature, you notice
little difference between a locally running application and a remote one. From
the user's standpoint, all computing is occurring on the WinFrame server. Your
local client receives and sends only a minimum of information. The result is
remote application execution that rivals local execution. (You can also run
Windows applications on the Internet at 28.8Kbits per second--Kbps--or even at
Integrated Services Digital Network--ISDN--speeds, using the ICA protocol that
makes WinFrame so fast. A beta version for this purpose is available from
Citrix's Web site at http://www.citrix.com/hotspot.htm.)
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