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XTM Compatibility with HP 200LX
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How to use XTM to run HP 200LX software on EPOC32 |
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What was the HP 200LX? The Hewlett Packard 200LX was a palmtop computer that ran the MS-DOS operating system. It was very similar in size and weight to the Psion Series 5 family, although the screen was a little smaller. The technical specification of the hardware is directly comparable to XTM - it had an 80186 processor, and provided a CGA display, but only in monochrome. Like XTM, the HP machines could run most standard DOS software. To make the machines into a convenient Personal Information Manager (PIM) HP also added their own task switching environment on top of DOS, called the System Manager, and included a graphical user interface. This proprietary DOS extension is not included in XTM, but the low level graphics routines it uses, the so called "Int 5F" functions, are. These let you run most HP 200LX software on XTM as described below. Standard DOS Programs One of the reasons for the popularity of the HP 200LX was that most DOS programs would run on it. Both off the shelf and custom applications could be downloaded onto the palmtop machine and would run anywhere. The same is true of XTM. Any standard DOS application that runs on an HP 200LX will run on XTM.
Series 5 running Lotus 1-2-3 - Click for full-size image A useful feature of the HP machines is that the screen can be zoomed to make text more readable, and a number of custom applications for the HP rely on this, fitting their text into no more than 18 lines. The text mode Zoom offered by XTM on the Psion Series 5 reproduces this and also displays 18 lines of text. Palmtop Graphics Applications A number of development tools allow programmers to make use of the HP 200LX graphical user interface and write programs that look like the built-in applications. The best known is the Palmtop Applications Library (PAL), and there are several utilities and games that have been written using the PAL library. For many more examples, try the S.U.P.E.R. archive.
Series 5 running FreeCell - Click for full-size image Because XTM includes the low-level graphics drivers needed to run PAL applications, these programs can be run directly from the DOS prompt in XTM. You do not need to install a 3rd party graphics driver like INT5F.EXE or CG.COM to run stand alone PAL applications. System Manager Applications The proprietary HP System Manager interface included not just a graphical user interface, but also provided a database engine, task switching and message passing utilities. The System Manager is not included in XTM. Fortunately it is possible to buy a version of the System Manager, along with the basic PIM applications of the HP palmtop. Hewlett Packard produced a product called the Connectivity Pack which was designed to run the PIM applications on a desktop computer under DOS and support development of third party applications. This same product will run on XTM, and can give you all the capability of the HP palmtop on an EPOC32 machine.
Series 5 pretending to be an HP 200LX by running Connectivity Pack There is just one thing to watch out for before using the Connectivity Pack. One of the components in the Connectivity Pack is an implementation of the Int 5F graphics interface called CG.COM. This driver is designed to run on a desktop PC with an EGA or VGA display, and it will not run on a machine with a CGA display like XTM. Fortunately we don't need it, because we have the Int 5F driver built-in. Before launching the Connectivity Pack on XTM you must therefore change the batch file that launches the System Manager to remove CG.COM.
Series 5 running HP Phonebook - Click for full-size image The following is our simple replacement for the standard batch file that launches the Connectivity Pack: UN200.EXE Differences to watch out for There are some limitations when it comes to running HP 200LX applications under XTM. The most obvious is the keyboard layout, especially the function keys. The 200LX has a row of 10 function keys along the bottom of the screen, and most 200LX applications use these as "soft keys" by painting labels at the bottom of the display. XTM's function keys are at the top of the screen, and it can sometimes be difficult to identify which function is mapped to which function key. What's more, there are keys on the HP keyboard (such as a numeric keypad) that are not available on a Psion keyboard, so some keystrokes may not be available at all. Some 200LX applications rely on intimate knowledge of how the hardware works - obviously they will not be portable to XTM. Finally, battery life for an HP 200LX application running on XTM will be lower than the corresponding life on a real HP 200LX. This is not because the EPOC platform is a poor design, but is simply because the emulator must execute many CPU instructions under EPOC for each instruction on the HP 200LX itself. |
