MetaFrame Presentation Center for Unix

Although this book is primarily focused on MetaFrame XP for Windows 2003, UNIX-based applications continue to be a mainstay of many large enterprise environments, and Windows and UNIX users alike can benefit from seamless, single point, webified access to these applications. Because of the overall value of server-based computing in providing web-based seamless access to all applications from any device, for all users, the authors felt strongly that MetaFrame for UNIX should be covered in this book. A large majority of the features and infrastructure discussed in these pages will apply equally to MetaFrame Presentation Server for UNIX and MetaFrame XP for Windows 2003. Features and tools such as MetaFrame Web Interface, MetaFrame Secure Gateway, load management, and any-device access are further promoted by bringing the UNIX applications to the Citrix SBC infrastructure fold.

Although some long-time UNIX administrators argue that UNIX has supported multiuser functionality for years through X-Window, and thus MetaFrame for UNIX is not needed, they are missing out. Due to the feature-rich GUI environments of most UNIX desktops and applications, X-Windows (even compressed X) is very network-intensive. Because of this nature, costly WAN topologies need to be implemented, and low bandwidth connections are almost non-supportable due to performance issues. Additionally, X-Windows does not support such MetaFrame features as shadowing, copy and paste of both text and graphics between the local client and remote server environments, autocreation of local printers and client drive mapping, and most importantly, Web Interface integration with Windows and web applications.

Based in part on the success and popularity of MetaFrame XP in the Windows application hosting environment, Citrix recently announced the latest version of the MetaFrame product suite aimed at the hosting of UNIX, X-Window, and Java applications: MetaFrame for UNIX Version 1.2. The product, which at present supports IBM AIX, Sun Solaris, and HP-UX platforms, as well as virtually any custom or commercially packaged UNIX applications, offers the same value as MetaFrame XP, but with a UNIX/ Java twist: low-bandwidth, universal client access over any network connection to any UNIX or Java application.

At the core of the MetaFrame for UNIX product is a modified X11R6.3 server. This does not replace the X11 server supplied with most UNIX operating systems but is specifically used to enable ICA-connected sessions running on MetaFrame for UNIX. MetaFrame for UNIX runs all standard X11 applications using the modified X server rather than the native X11 server.

In operation, the modified X11 server talks to a UNIX-ported ICA stack (Winstation Driver, Protocol Driver, and Transport Driver), which performs an X-to-ICA conversion. This is key to delivering applications seamlessly to clients from all MetaFrame platforms.

In addition to the modified X11 server and ported ICA stack, MetaFrame for UNIX also provides an ICA browser for use in load balancing and client browsing, a "listener" to intercept incoming ICA connections, and a "Frame Manager," which manages all the sessions currently running on the server.

The same core functionality used by MetaFrame for UNIX to deploy X11 and other applications hosted on UNIX servers can also be applied to Java applications. At first, this capability may seem redundant: in theory, Java applications are already portable to any device. In reality, however, Java client-side application deployments still confront numerous challenges.

Downloading Java applications entails the use of the available client-server network protocol, which is often not optimized for low-bandwidth connections. This results in the major complaint about Java applications—that they are sometimes incredibly slow to download for operation. Operating the Java application, which is executed locally on a server, over a bandwidth-optimized ICA connection provides a higher performance solution to this issue.

Java applications also fall prey to peculiarities in the Java Virtual Machine that runs on the client system. Not all JVMs are the same, and it is often the case that a Java application that runs perfectly in one JVM behaves very differently in another. MetaFrame for UNIX solves this problem by executing Java applications within the server's JVM environment.

Utilizing a single, server-based JVM also saves time and money when developing and testing Java applications developed in-house. Once the application is working in the server JVM, it can be deployed instantly to any ICA client device.

It should also be noted that the Java Virtual Machine is typically a large piece of software. While the development of an embedded JVM is under way, ultra-thin client devices lack the capacity to run a JVM that offers sufficient features or performance. This issue is removed through the use of the MetaFrame for UNIX solution.

In summary, MetaFrame for UNIX Operating Systems can be an important adjunct to Windows-based MetaFrame servers in heterogeneous server environments. MetaFrame for UNIX can be included in server farm and load-balancing schemes, and applications hosted on MetaFrame for UNIX systems may be published individually or as part of integrated Web Interface Access Centers for integrated access by end users.