Host Access Solutions: Terminal Emulation Software and Host Integration

Comparing Activex and Java Web-Based Emulators

Web-based 3270, 5250, SCO ANSI, Wyse 60, VT100, VT220 and VT420 Host Access

ActiveX, a component architecture developed by Microsoft®, allows applets to be downloaded from a web server and executed within a web browser. Java™, a programming language and component architecture developed by Sun Microsystems, also allows applets to be downloaded from a web server and executed in a web browser. Java™ applets can be run in various web browsers including both the Microsoft® Internet Explorer and Netscape Navigator.

Java™ Virtual Machine

Java™ applets are compiled into an intermediate code known as byte code, which is then interpreted by a virtual machine. The virtual machine runs within a web browser, and the web browser on top of the operating system. Because Java™ is an interpreted language and there are many layers of software, the compilation and interpretation causes Java™ to be significantly slower than ActiveX. There's more.

Byte Code vs Full 32-bit Code

Java™ applets, once downloaded to the browser, contain 8-bit byte code. ActiveX components on the other hand contain full 32-bit native code. This is one more reason why Java™ is significantly slower than ActiveX components. To correct this, Java™ JIT (just in time) compilers have been introduced that compile the 8-bit code into 32-bit code during the download and execution of a Java™ applet. And while this has increased the speed of Java™ applets, it's not been enough. How does this compare to the Microsoft® solution?

Applet Download

ActiveX components are only downloaded the first time they are accessed and each time a new version of the software is updated. On the other hand, Java™ applets are downloaded every time they are accessed, which has the potential to add to network congestion. There are some configurations for specific Java™ applets that use caching to store the applets locally, but this entails additional administration and may not work on all platforms or with all web browsers.

Java™ Interpretation Issues

Since Java™ virtual machines must interpret Java™ byte code, during the execution of the Java™ applet it must also translate Java™ library calls into Windows operating system calls. From time to time there are no one-on-one mappings between Java™ API and Windows API calls. These discrepancies can result in reliability problems, especially with host printing, user interface automation and advanced terminal emulator functions.

ActiveX - True 32-bit Windows Code

Since ActiveX is tightly integrated with the Microsoft® Windows operating system and IE web browser, all Windows API functions are available and called directly. ActiveX provides the same degree of reliability found in thick clients designed for Windows. This consistency makes ActiveX solutions more reliable.

Write Once, Run Anywhere?

Portability is the main advantage of Java™. The original idea behind Java™ was to be able to "write once, run anywhere", at least this is the idea that Sun and IBM® promote. However, Microsoft® views Java™ as a programming language and has decided to optimize the language for its Windows operating systems.

If a Java™ applet is written to be 100% compliant with the Sun Microsystems Java™ 1.1 specification, the applet will most likely run on a number of various platforms: Internet Explorer, Netscape, Sun, UNIX® and other systems that have Java™ virtual machine. However, if a Java™ application is written using the Microsoft® Visual J++ development software with the Microsoft® extensions, it most likely will not run on a Sun Java™ virtual machine. With the dominance of Windows, its not surprising to find that the majority of web-enabled client applications have been written using Microsoft® Visual J++.

Because the Java™ language has splintered in two directions, the "write once, run anywhere" idea is being tested. Also, Microsoft® is working on the ability to port its ActiveX technology to other platforms other than Windows, including Macintosh and UNIX®. Long term, this issue has yet to be decided.

Security with Java Virtual Machine

The original Java™ 1.0 virtual machine had many restrictions that promoted optimum security. These restrictions prohibited the Java™ applet from writing to the hard disk, accessing the printer and communicating with IP host addresses other than the machine it was downloaded from. For WEB TO HOST applications, the restrictions would prevent file transfers, host printing, or access a host mainframe using other 3270 servers. With the Java™ 1.1, these restrictions were eliminated.

Security with ActiveX

ActiveX components also have the ability to write to the hard disk, use the printer and communicate with IP host addresses other than the machine it was downloaded from. Because of the fear that a malicious ActiveX Java™ applet from an unknown source could destroy a user's hard disk, Microsoft® instituted digital certificates. A digital certificate guarantees that a downloaded ActiveX or Java™ applet is from a specific company and is certified by a reputable authority such as Verisign. Digital certificates guarantee that the signed applet hasn't been corrupted by a hacker.

Secure Sockets Layer

SSL security is also available for both ActiveX and Java™ web to host solutions. SSL is the de facto Internet security standard originally developed by Netscape and provides both authentication and encryption to prevent eavesdropping and tampering of your 3270 or 5250 host session(s). This feature can be critical for those organizations that remotely access the host across the Internet. PASSPORT supports SSL with both PASSPORT PC TO HOST® terminal emulation and the PASSPORT WEB TO HOST® terminal emulator.

Interface Issues

A benefit of using ActiveX is the consistent look and feel between Word, Excel or any ActiveX application. Applications that adhere to the Sun Java™ specification lose this benefit. PASSPORT WEB TO HOST® actually merges its menus with Internet Explorer and provides identical toolbars and button bars to those found in IE.

Windows XP/2000 and Internet Explorer

Windows XP and 2000 are even more tightly integrated with Internet Explorer. That's because the Internet continues to play a greater role in business and must be integrated throughout applications like Office 2000. This single factor could play a key role in determining the web platform of choice for most Fortune 1000 firms as they incorporate the Internet in eCommerce.

Conclusion

Java™ is a relatively new and maturing technology that holds many promises. Its major advantage is portability. However, its performance today is slow for advanced applications like terminal emulation. Reliability can also be an issue, due to the software layers introduced with the Java™ virtual machine. Java™ performance will be comparable with ActiveX performance once Java™ microprocessors are added to the motherboards of personal computers. Until then, ActiveX will offer significant performance advantages.

If Microsoft® Windows is a strategic computing platform for your company, an ActiveX web to host solution offers performance, reliability, features and ease of use advantages over Java™.

Quicktrial or Download Options

There are two ways to evaluate the PASSPORT WEB TO HOST® terminal emulator: either download a copy of the software or do a QuickTrial of the PASSPORT WEB TO HOST® application. With QuickTrial, there is no server installation, you simply download the client and run the application from our web server. This is a fast and easy way to look at the PASSPORT WEB TO HOST® software. For those that want to install the PASSPORT WEB TO HOST® software on their own web server, you can download the fully functional 3270, 5250, SCO ANSI, VT100/VT220/VT420 and Wyse 60 emulator trial and complete a full evaluation.