Several forthcoming products promise to bring thin-client computing to today's Windows applications, but experts warn: Look (and test) before you leap.
Dave Andrews
Microsoft's Terminal Server (MSTS, code-named Hydra) software promises to bring the benefits of thin-client computing to today's Windows applications. But managers who have successfully rolled out thin Windows implementations warn that you should plan and test before you deploy. And at least one Microsoft competitor, Corel, is rewriting its business applications suite to work better when running in multiuser mode.
MSTS adds multiuser capabilities and support for thin-client devices to applications that run on version 4.0 and future versions of NT Server. MSTS recently entered its first round of beta testing and is currently slated for release during the first half of this year, although that date could change, depending on how the first round of beta testing goes.
A thin MSTS implementation differs from a Java-based network computer (NC) in several key areas. For instance, an MSTS terminal doesn't download the OS or applications over the network, and it doesn't execute application logic locally. Plus, MSTS works with Windows applications that already exist.
MSTS has three components: the terminal server, the remote desktop protocol, and the terminal-server client. Microsoft says that any well-behaved 32-bit Windows application that runs on NT Server 4.0 is a candidate for multiuser deployment using MSTS. With MSTS, all application processing takes place on the server; only changes to the user interface are sent to the client.
In its base configuration, MSTS supports Windows-based terminal devices (available from a variety of vendors, including Boundless, Neoware, Network Computing Devices, and Wyse T
echnology, at prices as low as $500) as clients, plus PCs running Windows 3.11, 95, or NT. Support for 16-bit Windows clients means that MSTS can usher into the Windows 95 age meek, older hardware that has minimal RAM and is capable of running only Windows 3.11.
Microsoft's Windows-only client support is bolstered by a forthcoming extension to MSTS called pICAsso, from Fort Lauderdale-based Citrix (whose WinFrame technology already delivers capabilities similar to those of MSTS). pICAsso, which is slated to ship in the same time frame as MSTS, adds important enhancements, such as load balancing and support for a wide range of network protocols and non-Windows clients and devices (
see the table
for more information). Both products promise to reduce the cost of ownership through centralized application management and deployment and reduced hardware costs, without requiring you to rewrite your current applications.
But it's not quite that easy. Managers who have rolled out multi
user Windows implementations based on Citrix's WinFrame say such an exercise can be positive, but you need to plan for and test a number of components before deploying successfully. The same will be true for MSTS and pICAsso, they say. One potential area of concern is the Windows applications themselves.
One issue will be whether the application you want to deploy is reentrant. If it's not, then the server must launch a separate instance of it for each simultaneous user, which can quickly add up to a major load on the server.
In addition, Microsoft says that applications must be written correctly to run on MSTS. They need to properly separate global registry data from local (i.e., user) registry data, store user-preference files in the correct directories, and so on. Microsoft officials admit that they don't know how many of today's applications will work correctly in an MSTS environment. "That's one of the things we'll be looking at during Hydra's beta testing," says Craig Cumberland, Windows NT
Server product manager.
Another consideration: With MSTS and other MultiWin environments, all graphical output and keyboard/mouse input flows over the network. Overlaid images, on-screen animation, and splash screens take longer to display over the network on an MSTS client. And memory leaks, which are troublesome enough in a single-user environment, are intensified in a multiuser environment. These troubles are serious enough that, as mentioned earlier, Corel is currently rewriting some of its applications for smoother multiuser performance.
"With today's Windows applications, there's a lot of unnecessary redrawing and other activity that goes on," says Paul Skillen. He is the director of software development at Corel, whose multiuser
Remagen
technology will be bundled with WordPerfect Suite 8, Enterprise Edition, an applications suite being rewritten for multiuser deployment and slated to ship this year (
see the table
for more information). "If you'
re using [current] Windows applications in stand-alone mode, you don't notice all this activity, but if it occurs over a network, applications can run a lot slower."
Making sure your application runs efficiently in a MultiWin scenario is just one of the things you need to consider, according to George Morris, senior LAN specialist at Bell Mobility. "Network capacity, network latency, the process for rolling out applications, application performance -- these all need to be evaluated," he says. Morris adds that his company currently has approximately 120 WinFrame 1.6 servers in two production clusters and that Windows-based terminals can be an inexpensive and reliable way to deploy Windows applications. "It can be extremely positive, provided it's been designed properly," he explains. "But you have to take a systems approach. This is not just another PC that you're dropping on the desktop."
Microsoft officials say that once MSTS is commercially available, applications will have to run correctly with
the technology in order to qualify to bear the Windows logo. This is welcome news for current WinFrame users, as the logo will indicate that an application works correctly in multiuser mode. Says Bell Mobility's Morris: "It sure would make life a lot less painful."
| Thin Windows Solutions at a Glance
|
|---|
| Product
| Server OS
| Clients/apps supported
| Network protocols supported
| Server requirements
| Server performance
| Client requirements
| Availability
| Price
|
|---|
| Microsoft Terminal Server (MSTS, aka Hydra)
| NT Server 4.0 (x86 version only) and future NT Server versions
| Native clients for Win Workgroups 3.11, CE, 95, and NT/any "well-behaved" Win32 application
| Current beta supports TCP/IP only, although this could c
hange
| 32 MB of base memory, plus 4 to 8 MB per user on the server
| About 15 to 25 simultaneous users per 200-MHz Pentium Pro
| 386-based PC with 4 MB of RAM or Windows terminal device
| Slated for release in first half of 1998
| To be determined, but similar to other BackOffice programs
|
| Corel Remagen
| NT Server 4.0 and 5.0; native NT for Alpha CPU; Sun Solaris in the future
| Native clients for Win 3.1, 95, and NT, plus numerous Java clients/any "well-behaved" Win32 application
| TCP/IP
| 32 MB of base memory, plus about 6 MB for each user
| At least 30 simultaneous users per 200-MHz Pentium Pro
| 66-MHz or faster 486 with 16 MB of RAM; moderate-speed Mac, Unix, and NC devices
| First half of 1998
| To be determined, but probably less expensive than MSTS
|
| Citrix pICAsso
| Same as MSTS (also requires MSTS add-on)
| Same as MSTS, plus Mac, Unix, OS/2, DOS
,ActiveX, and Java clients/same as MSTS
| TCP/IP; IPX/SPX; NetBIOS; SLIP/PPP direct/asynchronous
| Same as MSTS
| Same as MSTS
| 286 or higher; Windows terminals; NCs; appliances; wireless capability
| First half of 1998
| To be determined
|
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