Page 3

So, to provide integration of non-SNA systems into SNA, a solution must enter SNA at some point. These "SNA entry points" are at one of the PU's. Host based TCP/IP has its entry point into the PU5 on the mainframe. Channel-attached gateways, such as the Bus-Tech 3172-NT running Microsoft SNA Server also have PU5 as the entry point by emulating another SNA device. Other solutions emulate a PU2 and can have PU4 as an entry point. The bottom line here is that you must interface with some level of SNA in your integration solution. The I/O Concepts family of X-Direct products provide tremendous configuration flexibility by using a variety of SNA access points. Further, these products can create environments that allow other platforms to use the services created at these access points.

To grasp the power and flexibility of the I/O Concepts solutions, there are several additional concepts that need to be understood. They involve X-Windows, Graphical User Interfaces, and TCP/IP terminal connectivity.

X-Windows

The X Window System can best be described as a standardized client/server architecture that provides the ability to distribute graphics applications. Almost naturally, any new technology must have a conceptual twist. This is definitely true with the X Window System. The client and server roles are reversed when referring to where the application resides. So, generally, the X Server resides on the desktop and the client process, or application program, resides on a system that supports X clients somewhere on your TCP/IP network. The X applications on a UNIX system such as spreadsheets, process control displays, text editors, graphic drawing programs, etc., are clients of the desktop X server. The X server is also known as a multi-application, multi-screen display. Each display manages the functions of a mouse, the keyboard, and the physical monitor or screen. This management involves controlling the tasks of sending keyboard input to the proper applications represented by the display. In addition to pure X terminals, there are products that allow PC's and Mac's platforms to be X servers, by being an X server they can connect to UNIX platforms and display/use the UNIX client processes.

GUI's

This brings us to the concept of Graphical User Interfaces (GUIs) and how they can be applied to the X-Window System and the access of mainframe data . GUIs can be defined as powerful, standardized computer interfaces that allow the end user to control and customize a " friendly" and consistent screen environment. This screen environment consists of "buttons", icons, menus, sliders and windows that provide an interface between the user and the systems applications. The result of using or developing applications with systems that offer GUIs, is an undisputed and provable increase in end user productivity and operational accuracy. Further, The end user can monitor several applications simultaneously, cut and paste data between applications, or easily employ a large number of local application interfaces to automate almost any combination of functions that an end user can do interactively. One example would be setting up a macro program that opens files, scans the text for some keyword(s), if they are found, an executable is started that ftp's the file to some location for printing, processing, or storage. The subtle, and powerful, key here is that the end user and the capabilities of the data representation system, have ownership of the data on the screen. This is a major conceptual difference between GUI based data representation technology and standard 3270 device data representation.