Tablet: The Personal Computer of the Year 2000

Tablet will have the same dimensions as a standard notebook. This rectangular slab will look like an 8''x11'' monolith from the movie 2001 and weigh but a few pounds. Having neither buttons nor knobs, the front surface will be a touch-sensitive display screen. One side will have a credit card sized slit, while the other three sides support ruby-colored ridges. Here, we describe our vision in terms of its components, leaving the rest of the essay to prove that the sum is greater than its parts.

The I/O Surface

The most important part of any computer is its user interface. The front surface of Tablet is a high-resolution touchscreen, which yields slightly to pressure. With this single input device, we get the tremendous flexibility of a soft interface: from the low-resolution but traditional means of pointing with your finger to the higher-resolution available using a stylus. The touchscreen can emulate a mouse, or a soft keyboard---customized to the user's finger size and taste.

But if we are holding a stylus, why bother with the keyboard? We can write and draw directly on the surface of the screen, integrating text and graphics. And, if we wish, handwriting recognition software will convert our scrawl to typed text. Finally, this color display is more than just an imitation notebook page, it will be fast enough to support video communications.

Without question this is technologically achievable. Liquid crystal displays are inherently pressure sensitive, and the density is increasing fast enough that by 2000 they will be of laser printer quality and in color. The touchscreen resolution will mimic the finest ball point. Cursive character recognition systems with training and spelling correction techniques can achieve nearly 100% accuracy. Of course, no human or silicon system will recognize all handwriting, particularly from the medical community, but what isn't recognized will be highlighted in a different color and reentered by the user.

It might seem surprising that voice is not a major interface. Science fiction seems to specialize in talking to computers and listening to what they have to say. However, in many of the contexts where Tablet will be used, such as the classroom, the airplane, or a shared office, talking out loud will not be appropriate. This is not to say that speech is not a viable form of input for our design. A microphone and speech recognition processor will allow a user to communicate via speech if he or she chooses. Although dictating letters and memoranda is a skill which takes time to master, a system allowing the user to alternate between a speech-to-text mode and a text editor could spare the user a great deal of time in preparing reports---especially when the words that are spoken match words already appearing somewhere on the screen. In addition, there are circumstances where speech may be the only way a physically handicapped user could communicate with our computer. Our design has the flexibility of allowing the user to communicate in whatever way is desired.

The LaserCard Mass Storage Unit

To replace classical rotating-disk/movable head media, we propose LaserCard. These credit card sized optical RAMs will be a convenient, inexpensive, and physically robust data storage medium. Through data compression techniques, a single one gigabyte card will hold four hours of video or two thousand books from a personal library. People will carry them in their shirt pockets and trade them like baseball cards. The only moving part in the whole machine will be the lid which keeps the optics dry if we use it in the rain.

One gigabyte is a healthy chunk of memory. However, it is only twice the capacity of a compact disk. We will use LaserCard for convenience, but it is clear that the real databases of the world will have to be elsewhere but still easily accessible.

The DataLink

To get this easy access, we need communication capabilities. Thus, Tablet integrates a cellular telephone link. This will not only support voice but data communications as well. The ISDN standard combined with compression techniques is sufficient to transmit video at conference quality rates today.

To use this link for voice communications, we will need a microphone and speaker built into the unit. These are inexpensive and justified by other applications. However, for privacy, in most applications we will use a headset attachment clipped onto the infrared bar.

The Infrared Interface

Along three sides of Tablet will be an infrared bar interface through which Tablet will talk to its local environment: printers and projectors, stereo headsets and video cameras, toasters and roasters, other Tablets and just about anything else. Every smart device in the world will have its own unique 256 bit key so a simple protocol will enable devices to talk intelligently to each other. There are nowhere near atoms in the universe, so we need not worry about running out of keys. With infrared light, low bandwidth devices need not be physically connected while indoors. The infrared interface may be extended by repeaters stationed in large offices and clip-on optical cables to boost bandwidth to gigabaud rates.

What types of peripherals will people need? One of the most widely owned peripherals will be a tactile keyboard. The handwriting interface and simulated keyboard will suffice for portable applications, but for rapid text entry, nothing beats a good solid keyboard. Another extremely popular peripheral will be a lapel sized video camera. Charge-coupled devices (CCDs) make inexpensive and rugged solid-state cameras. The cameras will record meetings, electronic mail videos for instruction and personal communication, and digitize those printed documents which remain in the year 2000. The notion of digitizing documents is important, because a substantial number of printed documents will remain, such as old books and new contracts. After digitization, an image can be processed to cleanup and recognize the text to allow searching by keyword and context.

Tablet will have a GPS (Global Positioning System) receiver as a built-in component. GPS is an existing satellite-based system which enables objects to locate themselves in the world to within a few meters. By plugging in the Rand McNally Road Atlas LaserCard before a drive, it can provide us with the ideal route and parking place for that new French restaurant in the city. Its usefulness extends well beyond driving, however.

Theft is a significant problem in an academic environment; anything valuable that isn't nailed down vanishes. And Tablet is valuable. However, with the Global Positioning System (GPS), the machine will know where it is and with the cellular phone DataLink, it will be able to communicate this information to the proper authorities. Try and fence merchandise this hot!

The Traditional Computer

That aspect of our vision which deals with what we today call the computer, i.e. the processor and its memory, is rather mundane. It is clear that there will be mega-MIPs and giga-bits available to work with, but whatever processor we have under the hood is irrelevant to the rest of the design. Thus we avoid the temptation to guess the exact number of MIPs, the memory size, or the degree of parallelism of our machine.

We expect microprocessors to converge on generic designs, coming in fast, extra fast, and economy sizes as do memory chips today. There will also be standardization among user interfaces, to the extent that all will be constructed in layers, where all but the highest layer will be a universal standard. Running on these generic processors might be a standard version of UNIX coming out of its shell into a PostScript interface.

All circuitry will sit on the same six-inch wafer of silicon. Though silicon may sound old fashioned, more exotic technologies such as optical computers, molecular or chemical computers, or superconductors will not mature by 2000. Improvements in semiconductor processing and design technology of our wafer will make room for large graphics processors, analog and digital hardware for image processing, and much more.

Perhaps the most interesting special purpose processor will be a data compressor sitting between the memory and the main processors. This will permit video to be stored on LaserCards and transmitted over cellular phone links, because image expansion will occur at video rates. It is ironic that compression becomes even more important as memory capacity increases, because there is so much more to transmit and access.

Rechargeable lithium batteries will deliver all the power we will be able to use without running into heat dissipation problems.

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