Classic Computer Magazine Archive COMPUTE! ISSUE 144 / SEPTEMBER 1992 / PAGE G22

Pointers and drivers. (use of an input driver)
by Steve Vander Ark

A graphical user interface (GUI) such as GEOS handles routine commands with a pointer on the screen, which makes the computer a friendly place to work and play. Just point and click, and the computer leaps into action.

There has to be a link, however, between your thinking and the computer's high-powered magic. You need some way to move the pointer on the screen, some gadget that will translate your actions into electrical impulses the computer can understand. GEOS refers to these gadgets as input devices; you most likely refer to them as a mouse and joystick.

In order for GEOS to know how to interpret the signals from the device you're using, you need to provide it with a small bit of code called an input driver. You probably know that the input driver you install on your boot disk will be the one the system assumes you're using when it boots.

You probably also know that you can switch from one input driver to another from the desktop with an option on the GEOS menu. The joystick and the mouse aren't the only input devices around, however. GEOS 64 has drivers for two other popular gadgets: the light pen and the KoalaPad. For another thing, the drivers you get with GEOS aren't the only ones available--and aren't necessarily the best ones either.

As far as devices go, the best known are the mouse, the joystick, the Inkwell light pen, and the KoalaPad graphics tablet. Each device has its strong points.

The joystick is particularly well suited for games. Also, the Suncom Icontroller, a small joystick that attaches to the side of your 128 or 64, lets you keep your hands near the keyboard while working; this is handy while using geoWrite.

The mouse is perhaps the most versatile of the bunch; its proportional movement (in other words, the fact that it speeds up as it moves) makes it superior for maneuvering around the GEOS screen. Since the mouse is held roughly the same way a pen or pencil is held--in one hand and moved about on a flat surface--it's very easy to use for graphics in geoPaint or for object placement in geoPublish.

If a natural drawing posture is what you're after, though, the light pen is a logical choice. You hold it like a pen, obviously, and actually draw on the screen with it. For some drawing tasks, the light pen is perfect. Freehand artwork using the spline tool in geoPublish is a good example. On the downside, you have to hold your hand up to the screen all the while.

With the KoalaPad, you hold the stylus exactly like a real pen. Since you hold the writing surface with your other hand, this device gives the best combination of intuitive use and comfortable posture. Device drivers for both the light pen and the KoalaPad are included only with the 64 version of GEOS, however.

These official drivers for the pen and pad are far from perfect. For one thing, the light pen driver reads the button click from the button on the pen itself. This is fine for drop-down menus, but if you're positioning graphics or trying to hold the end of a spline in place, you can't press the button without serious jiggling. This makes using the pen for graphics virtually impossible.

Q-Link has a solution in the form of an alternate driver called PenJoy (filename: PENJOY, uploaded by Mystic Jim). Instead of reading the button on the pen, PenJoy reads the button of a joystick plugged into port 2. Even with the best of alternative drivers, though, the response of the pen to the screen in GEOS is poor. The pen frequently misreads the screen, which in geoPaint results in stray and scribbly lines.

The problem with the KoalaPad driver is that it translates the position of your pen on the pad literally to a position on the screen. If you don't have the pointer "attached" to your pen position, such as when a drop-down menu opens and the pointer is arbitrarily placed on the first choice, you have to scratch around trying to snag the arrow's position with your stylus. Chances are you'll miss it or accidentally move it away from where you wanted it. The precision with which you can move the pointer is less than exact as well.

A new KoalaPad driver available on Q-Link addresses these problems; it's filename is KOALA PAD III, uploaded by SYSOP PH).

There are input drivers available on O-Link for the mouse and joystick as well. You can get mouse drivers that use port 2, that allow you to double-click only with the right button--not the left--and that switch your 128 into 2-MHz mode. You can also find drivers for Supersketch and the Atari trackball on Q-Link.

Which device is best? I've used them all with various drivers and in most applications, and I'll put my money on the mouse. There's simply no input device that works as smoothly and precisely or feels as natural as the mouse. It works better for freehand drawing than either the light pen or the KoalaPad, and it scoots you around the desktop more quickly and efficiently than the joystick.