Although network computers and Windows terminals have yet to catch on, thin-client computing still has a significant role to play in the distributed applications strategies of some organisations. Linking desktops to remote application servers enhances security, centralises management and monitoring, pools valuable per-seat licences, and saves money on desktop upgrades.
Using Windows NT Terminal Server Edition, you can turn any Windows program into a distributed application. But you're limited: only users currently running Windows can connect as clients. Citrix Systems' MetaFrame extends Terminal Server's reach to clients running Unix, Linux, DOS, or Mac OS. In addition, most systems supporting Java should be able to connect to MetaFrame servers.
I evaluated MetaFrame, release 1.8, an upgrade that improves performance, supports more client platforms, and blends in several features targeted towards the enterprise.
Release 1.8 extends MetaFrame 1.0's support for server farms, or groups of servers that share the burden of running selected applications. An extension of the client Program Neighborhood simplifies client connections to applications served by the farm. Users can create their own Program Neighborhood shortcut icons and administrators can push newly published applications onto client desktops. Double-clicking an icon in Program Neighborhood bypasses server selection and log-in, and even silently chooses a backup server in the event of another's failure. Through MetaFrame's server farm concept, you can publish applications that run on any server in the farm, effectively distributing the load and covering server outages. The users need not be aware of any of this. They just double-click on an icon, and off they go.
Client systems that have attached local printers will also benefit from the new release. Rather than restricting users to those printers that MetaFrame servers can see, users are free to create links to their desktop printers. This also makes it much easier for non-Windows users to print to locally connected devices.
I was intrigued to find support for Linux added to this release. Citrix has created native Linux executables that run under the X-Window system, just as the Unix clients do. I tested the new client under SuSE Linux 6.0, and it worked: I was connected quickly and the performance was quite acceptable. The Linux client is noticeably slower than its Windows counterpart, but the decrease in speed is offset by the fact that Linux, unlike Windows, costs nothing. That makes it, for some, an ideal MetaFrame client. Citrix has also added client support for SCO Unix to this release.
Citrix has tweaked its Independent Computing Architecture (ICA) transmission protocol yet again. It has added more repaint optimisations, and claims a reduction in network traffic of 25 per cent to 30 per cent. The company has reduced the total packet count as well, giving a break to users who are using dial-up and other low-speed or multihop links.
MetaFrame 1.8's performance looks solid, but it is no miracle worker. I set up a torture test using multiple Linux clients displaying a heavily animated Web site. While the clients were banging away on the MetaFrame server, I fired up a remote copy of Word on a Windows client. Displayed characters lagged and cursor movement within a document was sluggish and then sudden.
Still, understanding the technological ceiling under which MetaFrame must operate, I considered its performance under duress to be quite impressive. It proved to me that under more realistic conditions, where few if any users are redrawing huge tracts of the screen several times a second, MetaFrame will deliver satisfying interactive sessions.
MetaFrame 1.8 installed quickly and easily. You are given an installation key when you buy it, but you must still electronically register it within 30 days to keep it from shutting down. You will get a nag screen every time a user logs in until you register. That's a bit draconian; I would almost prefer a dongle.
MetaFrame 1.8 still displays a maximum of 256 colours on clients, a relief for your beleaguered LAN, but a potential showstopper for those applications that expect the now common true-colour display. Even so, with additional clients, enhanced local printer support, improved fault tolerance, better performance, and easier client launching, MetaFrame 1.8 is a required upgrade for any shop currently running MetaFrame.
The lure of being able to run Windows applications on Linux clients may help entice those tired of paying Microsoft's desktop operating system fees. Whatever brings you to MetaFrame 1.8, you will be well served by this tight, easily managed Windows application server.
Tom Yager (firstname.lastname@example.org) is a project lead at Healthweb Systems, in Irving, Texas. He specialises in application development, databases, and operating systemsThe bottom line: very goodMetaFrame, Release 1.8This program extends Microsoft Windows NT Terminal Server Edition to support non-Windows clients, and adds some fault-tolerance and load-balancing features. It's a fine product for connecting disparate clients to your applications.
Pros: Easy to install and manage; good performance; wide array of clientsCons: Limited to 256 colours; cumbersome licence registrationCitrix Systems, Fort Lauderdale, Florida; www.citrix.comPrice: $US4995 for 15 users; additional licences range from $995 for five users to $9975 for 50 usersPlatforms: Server: Windows NT 4.0 Terminal Server Edition; Clients: 16- and 32-bit Windows, DOS, Mac OS, HP-UX, AIX, Solaris, Sun OS, Irix, Digital Unix, SCO Unix, Linux, and many Java-enabled OSs