The legend of the pad of power. (evaluation) Joe Devlin.

Once upon a time, around 1982 to be precise, four magical people met in a faraway land known as Georgia. They looked into their crystal balls and determined that the next boom in personal computers would be in the area of educational software for the home. They looked around and saw that, throughout the country, little home learning software of quality and imagination was available. And it came to pass that they created Chalk Board, Inc. for the purpose of rectifying this tragic situation.

The quest for new and novel software proved hard. The more time these magicians spent trying to write enchanting programs, the more frustrated they became with the hardware the sofrware was supposed to run on. To cast their spells on children, to make children want to learn with computers, the Georgians hand to communicate with the kids.

Now, children are interesting creatures, very different from you and me. Even children who know the alphabet don't always have the manual dexterity required to use a computer keyboard. They don't understand bar code readers very well. And, although kids can learn to use light pens and screen-oriented menus, parents are often uneasy when their children stand for hours in front of color televisions and poke at the screens with sharp objects.

The magicians pored over their books of spells and almost emptied their bags of tricks. What they wanted was an input device that was flexible, sturdy, easy to use, inexpensive, and portable. It should be large enough to sit on a child's lap and sturdy enough to take childish abuse. It should be portable enough for a child to carry around, and it should have a cable long enough to allow the child to use the device while sitting on a couch or on the floor near the TV. They concluded that it they wanted a piece of hardware to fit their needs, they would have to conjure it up themselves.

Thus, Chalk Board, a company founded to produce software, ended up creating hardware to meet its software goals. Because the device they created is a pad of great power, they named it Power Pad. Its power is such that children and adults alike will soon be found curled up on couches throughout the land entranced by its spell. Its utility is such that many programs are being written to make use of the magic it wields. The Magic Begins With The Hardware

The magic of Power Pad is that it is a tabula rasa. Thus, it can be set up as the input device for an infinite variety of software. With a chance of software and a flip of a plastic overlay, Power Pad can go from being a graphics pad to being a piano keyboard.

The pad retails for $99.95. For this you get the large (17" by 20") off-white pad complete with a big slot of a carrying handle, cabling to hook the contraption up to any Commodore 64, Vic-20, or Atari computer, and a user's manual.

The software required to use the pad must be purchased separately. The cabling that comes with Power Pad will not work with the IBM PC or with the Apple II. Hooking the Power Pad up to an Apple or an IBM computer requires the additional purchase of a $49.95 starter kit. This kit includes both the software and cables required by these two computers.

At the heart of the pad is a touch sensitive membrane invented by some of the Chalk Board people. This membrane lies in the 12" by 12" working area in the middle of the pad. Along any horizontal or vertical line there are 120 switches. The resulting 100 switches per square inch give the Power Pad the highest resolution of any touch-sensitive device I have seen.

One of the most unusual features of the Power Pad is its ability to respond to more than one point of contact at a time. Most touch-sensitive input devices can register contact with only one point at a time. Power Pad can determine that it is being touched in several places at once through the use of the 14,400 digital switches beneath the surface. As a result, you can press your whole hand down on Power Pad and produce an image of the hand on the computer screen.

By itself, the hardware is just another example of a nice graphics tablet in a market that is rapidly becoming crowded with such devices. But there is more. Chalk Board is also producing a library of software and removable membrane overlays that completes the process, turning the product into something that dazzles.

By redefining the pad as a keyboard for particular applications and by producing individual overlays that guide the user through the use of this new keyboard, relatively complex things can be done easily. The size, location, and function of each key is determined by the software designer. The programmer is not stifled by the fixed spacing of a normal keyboard.

Each overlay can be imprinted with a distinct arrangement of color coded areas that serve as both menu and function keys. Pressing one of the mylar squares activates the function controlled by the software and indicated by the markings on the plastic overlay.

As software and mylar overlays are changed, the Power Pad can become in turn a keyboard arranged alphabetically so as not to confuse children, or a keyboard with extra large keys for those whose eyes have dimmed. Musicians can have a piano keyboard, with every key functional. The multiple registration feature allows musical chords to be played on the Power Pad instead of the single notes possible on most graphics tablets. Software Weaves Its Spells

The Chalk Board software, dubbed Leonardo's Library, will eventually include more than 30 software packages, spanning six subject areas (visual arts, music, mathematics, science, language arts, and social studies) and five levels of difficulty. Not all the software available for Power Pad will come from Chalk Board. Other firms are currently converting software for the Power Pad or writing new software that makes full use of the capabilities of the product.

Chalk Board plans to make each software package they offer available for the Commodore 64, Vic-20, Atari, IBM-PC, and Apple II computers. Obviously, because of profound differences between the capabilities of these machines, the power of the software will reflect the strengths and limitations of the machine it is written for. Software for the Commodore and Atari computers will be in cassette format. IBM and Apple computers will make use of disk-based software.

Each software package will include a tough plastic overlay that is imprinted with function buttons and a manual describing several learning activities. Prices for software will range from $24.95 to $49.95. There will be at least three software packages available initially.

The MicroMaestro is a music package that turns the PowerPad into a fully functional two-octave music keyboard and synthesizer. It will retail for $24.95.

Leo's Logo will retail for $49.95. As its name implies Leo's Logo will use the PowerPad to bring the Logo language to the child. The third software package is a graphics tool called Leo's 'Letric Paint Brush. Leo's 'Lectric Paint Brush

Leo's 'Lectric Paintbrush is a graphics package that retails for $24.95. It is a good example of the kind of software that Chalk Board is planning to release. Getting started is easy. Insert the software cartridge into the back of the computer, plug the PowerPad cable into the computer, snap the mylar overlay into place on the working surface of the PowerPad and Leo's Paintbrush is ready to use.

There are 21 symbols printed on the top of the overlay. Most noticeable are the color keys on the top right. There are eight labeled colors--black, white, red, cyan, purple, green, blue, and yellow. Touch any of the color keys and a musical note emanates from the TV speaker letting you know that you have chosen a color. Touch the keyboard with your finger and a spot of colored light appears on the screen. Slide that same finger across the surface of the pad and a line appears on the screen.

You are free to draw with one finger or many. The pad responds best to slow, even motions. One of the limitations of the program is that it uses only eight colors, in spite of the fact that some of the computers it will run on have more colors available.

If the line produced by your finger is too broad you can use a blunt stylus to get a finer edge. The finest line I was able to achieve on a Commodore 64 was about the width of a matchstick. Using the PowerPad with the IBM PC or another computer with better resolution should produce better results.

Many of the other keys on the mylar membrane are as self explanatory as the color keys. For example, hitting the Background key followed by a color key will change the background color. The Pen Up and Pen Down keys are used to indicate which points are being pressed on the membrane. Hit Pen Up, and a tiny ink-filled pen appears on the screen letting you know where you will begin drawing when you hit Pen Down. If you touch more than one spot at the same time, the pen will jump from spot to spot on the screen indicating all the various points of contact.

Press Pen Down and you activate the paint brush; the little pen point disappears and in its place a small dot appears. You are now in drawing mode.

The Fill key is used to fill in solid objects on the screen. Again, its operation is logical. Position he pen on the space you want to fill, hit the Fill key followed by the color you want to fill it with. Voila! The object fills with color. The Fill key will fill any closed-in space. If there is a hole, even a miniscule one in the object, the color will leak out of the object, like water from a broken vessel, filling not only the object but the rest of the screen as well. If this happens, hit the Cancel key to stop the overflow of color, and you can resume your artwork.

The functions of some of the other keys are less apparent than those of the color keys. For example, Asterisk and Hashmark keys serve as general function keys to do such things as calling forth the memory grid. The functions of two keys labeled To and End may also be a puzzle to the uninitiated. The fact that the End key is emblazoned with a flag did not help to clarify matters for me.

These two functions have been borrowed from the Logo programming language. The To and End keys are used to indicate the starting and ending points of the definition of an object. Once an object has been defined, it can be moved about or copied to other parts of the screen. To start the operation, first hit the To key. Next draw the object--say, a red circle. Hitting and End key tells the computer you have finished drawing the circle.

Defining objects uses up a great deal of computer memory. To find out how much space you have left, you can call a bar graph onto the screen to indicate the amount of memory space left by hitting the asterisk key.

The number of objects that can be saved depends on the computer with which the PowerPad is used. For example, up to nine objects can be defined within the memory of a Commodore 64. Hitting the Clear and Asterisk keys together undefines all objects, thus freeing memory and giving you space to define new objects. The screen does not change when this is done.

The red circle remains on the screen. Undefined objects do not disappear but they cannot be moved or duplicated again.

Once objects have been defined you can do several things to them. Any object that has been defined can be repeated anywhere on the screen or moved from its original location to a new location simply by hitting the Repeat or Move key, touching the object you wish to move, and then touching the spot to which you want it to go.

Objects can be saved on disk or cassette. Since there are no alphanumeric keys on the membrane, the objects are named by using the color function keys. Thus, you could name one object "black-green-red" and another "blue-yellow." Limitations

The PowerPad is flexible input device that will stimulate the imaginations of programmers--even those who don't come from the mystical land of Georgia. The product does have a few limitations, however. A flat membrane keyboard cannot provide as much comfort or tactile feedback as a full stroke keyboard would provide for an adult.

Although the PowerPad case is quite sturdy, the mylar overlay is more fragile. Sooner or later someone is bound to cast his spell with a ballpoint pen or scissor point. The wise folks at Chalk Board have forseen this problem and are making overlay replacements available for $6.00.

In short, the people at Chalk Board seem to know what they are doing. And so the wizards from Georgia presided over a happy marriage of hardware and software. And they lived happily ever after.

Products: PowerPad (computer apparatus)