Browse Prior Art Database

Method for Disconnected Host Terminal Emulation Disclosure Number: IPCOM000013622D
Original Publication Date: 2001-Feb-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 3 page(s) / 90K

Publishing Venue



Disclosed is a software method for emulating a terminal device while it is disconnected from a host.

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Method for Disconnected Host Terminal Emulation

Disclosed is a software method for emulating a terminal device while it is disconnected from a host.

The demand for pervasive computing devices in the business environment has been increasing rapidly. The need to access to existing business applications outside of traditional office locations is apparent. For example, in Japan, terminal emulation software has been one of the kind of products that fit well into the Japanese work environment and sell well. The employee works at a central location and connects directly to the host. As the Web based environment grows, the cost of maintaining a large central work location increases, and the use of mobile/pervasive computing increases. Employees would like to access the same applications from remote locations, such as while traveling. The need for light weight emulation support on mobile or pervasive computing devices, such as IBM's Host On-Demand product, is a major requirement.

One of the problems that needs to be solved in the mobile/pervasive computing environment is disconnected host terminal emulation. Users need to be able to interact with green screens disconnected while live connection is not cost justified, such as when the network bandwidth is low, expensive, or connection is simply not possible. The prior art does not provide such a capability. Emulation express technology is the closest that can reduce the traffic across the wires but live connections are still required.

This method provides a solution for disconnected terminal emulation by utilizing XML Host Access technology and macro record-and-play technology. The solution is appropriate for disconnected users with devices that have sufficient display window scrolling space, such as WinCE, Palm, and laptop. It is also appropriate for use in application development environments such as the Host Access MacroManager bean from IBM's Host On-Demand and the design studio of IBM's Host Publisher for marking up host application screens off-line.

The Method

A method is provided to record and save live host application interactions in local storage together with the screen images. Subsequently, the user can select to play the recorded interactions back in a disconnected mode and the saved screen images will be displayed accordingly. The recording method enables looping and conditional branching of screens thus controls the navigation of play back. Figure 1 is an overview of the disconnected terminal emulation process. The Host Integration host access macro scripting technology controls the recording and playback. Screen images are saved in the xmlHostData XML format. Each screen identified in the script points to an image. A disconnected mode processing is provided by the scripting engine (1) that always displays a screen image (2) and pauses for user inputs (3) before going on to the next screen. If the next screen is not in local storage (i.e. not recorded before), an error messag...