Video / ELECTRONIC ENCYCLOPEDIAS (Jul, 1984)
COMPUTERS AND VIDEO appear to offer an endless variety of combinations, as this month’s cover by Robert Tinney depicts. With an increase in higher-power communication satellites that require smaller, less-expensive user antennas and electronics, and with the melding of television receivers and microprocessors, we might look ahead to the day when worldwide person-to-person visual as well as aural communication is based on personal computers and not on a direct descendant of Mr. Bell’s original invention. “Bulletin Boards in Space.” described by John Markoff in the May BYTE West Coast column (page 88), may give way to worldwide electronic conferencing and conventioning by adding television cameras to the growing list of common personal computer user options.
Many videotex, work-alike, and other interactive cable-television-based systems already exist. With the proliferation of coaxial-cable interconnection and its high-speed data-transmission capabilities, more and more homes and businesses could be linked via computer-controlled video instead of the restricted-bandwidth, audio-frequency-based systems now in use.
Shopping via computer is already a reality in some areas. With television- or presentation-level graphics, perhaps complicated and expensive encoding schemes could become unnecessary because you might be able to view the person to whom your message is directed. And as Rich Malloy, our product-review editor, stated in the July 1983 BYTE in his introduction to the Videotex theme, the printing presses might stop and BYTE could be delivered to you electronically.
Though with us for over a generation, until recently hardware costs made computer and video interactivity limited and expensive. In recent years, dramatic advances in digital electronics and large-scale integration (LSI) have made personal computers, videocassette recorders (VCRs), and videodiscs available to anyone with a down-to-earth application or interest in learning. In this issue, we present articles on a wide range of topics related to computers and video.
Peter R. Cook’s article, “Electronic Encyclopedias.” explores something that all of the major encyclopedia publishers have talked about for several years: how to develop an “intelligent encyclopedia” that uses natural means of accessing and using knowledge. Included with this article is contributing editor Mark Dahmke’s look at “An Ideal Video Peripheral,” a glimpse at how personal computers and videodiscs might communicate more efficiently.
In ‘”televisions as Monitors,” Ken Coach describes some of the characteristics common to the new generation of television receivers that can double as microcomputer video monitors.
If you already have an inexpensive VCR with limited or no programming capabilities or are considering purchasing one. Cy Tymony’s “Computer Control of a Video Recorder” should be particulary interesting. This construction project enables you to use your micro as a programmable control center for your VCR.
Stan Jarvis’s “Videodiscs and Computers” takes a look at the videodisc industry, its evolution. and the myriad of companies and equipment facing personal computer owners.
As an example of what you can do with a CAV (frame-addressable) videodisc, Rod Daynes and Steve Holder designed a game around a generic version in “Controlling Videodiscs with Micros.” They used the videodisc support commands available in the Sony SMC-70 computer.
—Gene Smarte. Managing Editor
by Peter R. Cook
Interactive video technologies help explore “the realm of worthwhile knowledge”.
Peter R. Cook is vice president of creative services for Grolier Electronic Publishing Inc. (95 Madison Ave., New York, NY 10016). He is responsible for coordinating the development of that firm’s Multi-Component Electronic Encyclopedia, which is intended to combine videodisc and videotex technology. Cook spent five years at Arete Publishing Co.. producing the Academic American Encyclopedia.
ENCYCLOPEDIAS EVOKE special memories for most people. When you were a child, you probably did research for essays and class projects, looked for “naughty” words and pictures, struggled through dull facts about dead people, or discovered fascinating facts in articles from “Aardvark” to “Zygote.” Later on, maybe you used an encyclopedia to solve crossword puzzles, to help a child with homework, or to look up the location of a vacation spot or an unfamiliar country mentioned in the news.
Now there is a whole new range of associations that most people wouldn’t normally connect with an encyclopedia: on-line databases, videotex systems, and laser videodiscs—new interactive technologies that, at first glance, might appear to be the very antithesis of the traditional printed encyclopedia. But major electronic publishing companies are beginning to create a new generation of encyclopedias, powerful informational/educational tools that can interact through, and with, all of these new media.
As part of a long-range development plan, Grolier is creating a massive encyclopedic database of text and audiovisual materials that can be accessed and manipulated using interactive technologies. The two major components of this plan, the text database and the audiovisual database, currently are be- ing developed along separate but convergent tracks—one utilizes on-line or videotex technology, the other utilizes videodisc technology.
In this article, 1 will review both development tracks, observing from the publisher’s point of view how information is enhanced by delivery via new interactive technologies. But let’s begin with a look at encyclopedias delivered via a traditional interactive medium—the book. Though new technologies should not slavishly imitate those that preceded them, there is much to be gained by using the book metaphor for building the foundation of an information tool that utilizes the full power of interactive video technologies.
According to an entry in the Academic American Encyclopedia (AAE), a printed general encyclopedia “attempts to present the entire realm of worthwhile knowledge: the humanities and literature: fine, applied, and performing arts: science and technology: history and social sciences: critical issues such as bioethics and civil rights: and select data on significant places and persons.”
Mechanics and economics tend to limit the size of a printed encyclopedia’s “realm of worthwhile knowledge”: of necessity, the information itself is synthesized and summarized. Distillation and outlining of knowledge, along with broad coverage, make a general encyclopedia—whether it be in 1, 20, or 30 volumes—a useful reference tool.
The reference characteristics of encyclopedias are what brought about their rather unnatural, usually alphabetical, information structure. There is no inherent logic in grouping “Aardvark” with “Alvar Aalto” and “Hank Aaron,” although such curious juxtapositions often create wonderfully serendipitous discoveries. Diverse subjects are thrown together for no reason other than the fact that an alphabetical, dictionary-like organization improves access to information. Some encyclopedias still cling to the earlier thematic approach in which related information is grouped together. Thematic groupings make it possible for information to be viewed in a broader context, but highly specific facts are harder to locate.
Alphabetical encyclopedias compensate for the seemingly arbitrary arrangement of their articles by using in- tegrated cross-references that indicate the presence of related articles and draw connections between the various realms of knowledge. In its current (fifteenth) edition, the Encyclopaedia Britannica attempts to overcome the shortcomings of this alphabetic tyranny by breaking the set into three resources: Propaedia. a one-volume overview of knowledge; Macropaedia, a collection of in-depth articles (many of considerable length) on broad areas of knowledge; and Micropaedia. containing very short articles as well as discrete, specific facts. The attempt, however, is thwarted by the awkwardness of three integrated, but separate, resources.
While encyclopedias may have to struggle with the drawbacks of their own unique organizations, they also exhibit the positive characteristics of the printed book. Books are physical entities, portable random-access devices. Their organization is universally recognized: pages, chapters, tables of contents, prefaces, introductions, indexes, bibliographies, etc. They are the framework of written language. Other characteristics inherent in books let you browse through them easily and give you a sense of scale and place. You know how to navigate in a book.
But the book also has its limitations. It is a fixed medium: once printed, it cannot be changed. The only way for a user to update a printed encyclopedia is to buy a new one, write notes in the margin, or purchase the yearbook that most encyclopedia publishers issue annually to maintain the currency of existing sets. The information is also fixed in that it cannot be dynamically rearranged for the user’s convenience. Comparing all the articles on dinosaurs, for example, might require accessing more than a dozen volumes. Information access is also limited by the specificity of the article titles and by the quality of the index—nonindexed information is almost the equivalent of no information. Finally, no matter how descriptive the text or how informative the illustrations, no printed encyclopedia can capture the power of a place, person, or event more vividly than an audiovisual medium. Yet the printed encyclopedia is, and will continue to be, a highly valued information resource for most people.
Now consider an electronic encyclopedia that uses the full power of new interactive media and is designed to meet the needs of a new generation of users.
Electronic Reference Work.
In 1982, Grolier acquired the rights to the Academic American Encyclopedia, a new 20-volume general-reference work designed for use in homes and schools. Containing approximately 30,000 articles and 9 million words, the AAE is characterized by its currency and its short entry format (its articles have an average length of approximately 300 words). For us it had the additional virtue of being typeset entirely with computerized equipment, and thus it could be converted for on-line dissemination.
The electronic edition of the AAE has been in existence for two years and is currently available to over 250,000 online and videotex subscribers through existing information utilities. These include services such as CompuServe, Dow Jones News/Retrieval, BRS. Dialog, and Vu/Ttext. We also distribute through NAPLPS (North American Presenta-tion-Level-Protocol Syntax, or “nap-lips”) graphics-based systems: Viewtron, Keycom, and Times Mirror’s Gateway (which uses Telidon graphics, a forerunner of NAPLPS). Users accessing the encyclopedia remain customers of the information utility, which in turn pays Grolier a royalty.
The encyclopedia’s inherent data structure has to be adapted to the display characteristics and access protocols of individual systems. Because these system requirements have a considerable effect on how the user interacts with the encyclopedia, it is worth reviewing some samples at length, beginning with the less complex, and consequently less powerful, systems.
Viewtron: An ASCII/NAPLPS Hybrid.
Viewtron, operated by Viewdata Corp. of America (a Knight-Ridder subsidiary), is the first commercial videotex service to use NAPLPS color graphics, which can be accessed only by AT&T’s Sceptre terminal. This regional service is now available in just three Florida counties; if successful, however, the service will become available in major cities around the country.
Viewtron is a relatively simple menu-driven system that stores most of its databases on preexisting frames. However, because the AAE is a large database (by videotex standards), it is actually accessed through a communications gateway. The AAE text is housed on computers at Vu/Text (another Knight-Ridder subsidiary) in Philadelphia; the computers are linked by dedicated line to the Viewtron host in Miami. A user accessing the system is connected via the gateway as soon as he selects the AAE from a menu (see photos la through Id). The videotex terminal “paints” the appropriate NAPLPS frame, but it has an active window for displaying the ASCI! (American National Standard Code for Information Interchange) text from the Vu/Text gateway. The user is then prompted to type in a search term, which is matched against the AAE’s 30,000 article titles. If an exact match exists, the system displays the first 15 lines of the article and the user can “page” through the rest at his own pace. If the search term is too broad, a number of articles are selected. For example, if just “Lincoln” is entered for information on Abraham Lincoln, the system locates all articles with the word “Lincoln” in the title, including “Lincoln, Nebraska” and “Lincoln Center for the Performing Arts.” The first article is displayed with the qualifier “1 of n [articles],” and the subscriber can then use the system’s “browse” function to scan the first frame of each article.
ASCII (Non-Graphic) Videotex Services.
Dow [ones News/Retrieval and CompuServe are both consumer-oriented information utilities that primarily use keyword and menu-driven access. A subscriber logging onto Dow Jones News/ Retrieval is guided to the AAE via names and enters a search term or query that is matched against article headings. If the search term is in more than one heading, the system generates a menu, listing all of the articles, and the user selects from this (see figures 1a through 1e). If the selected article is long, an additional menu (or series of menus) is shown, providing a numbered outline of the contents. Thus, the user can select the most appropriate section without having to page through the entire article.
Dow Jones News/Retrieval also lists the number of pages or screens of text in each article and lets the viewer know which page he is viewing (2 of 14, etc.). CompuServe gives each page an individual number, which can be used in conjunction with the GO command to go directly to the page, bypassing the intermediate menu stages. As useful as these features are, menu-driven systems are limited. Access is through the article title only, which doesn’t open up the full potential of an electronic encyclopedia.
Free Text Databases.
Two much more powerful on-line database systems are BRS and Dialog. Considerably more expensive than the consumer databases, BRS and Dialog use free text search procedures in which every word in the database is indexed and therefore can be searched.
When accessing via BRS, a search term or query is entered using the required command language. However, if the search term is not properly qualified, the system may locate far too many occurrences to be helpful. For example, a search for “Einstein” produced several hundred “hits” (occurrences) of the word in 69 articles throughout the encyclopedia (see figures 2a through 2c). But the search can be narrowed down by using Boolean operators such as and, which combines two search terms in the same article: same, which combines two terms in the same paragraph; with. which combines them in the same sentence; and adj. which requires the two terms be directly adjacent. If what I really want to find out about Einstein is when he moved to Princeton, I would phrase the search as: “Einstein same Princeton,” which means I’m looking for the paragraphs in which both of the words appear. This narrows the hits down to just two paragraphs, which can be quickly displayed. These paragraphs tell me that Einstein moved to Princeton in 1933 and that he died there in 1955.
This simple example doesn’t really illustrate the full retrieval capabilities of free text systems. They can be powerful tools in the hands of an experienced researcher or librarian. On the other hand, their complex command syntax and Boolean search logic make them too complex for easy access by most untrained users.
In an effort to broaden the appeal and usage of their services, BRS and Dialog have both introduced easier-to-use and less expensive off-peak services: BRS After Dark and Knowledge Index, respectively. Communications software is also being introduced; Sci-Mate and In-Search simplify command procedures and enable the user to develop a search strategy before going on line. Such efforts are the first steps in what will undoubtedly be a series of software products aimed at making these information utilities (including Dow Jones News/ Retrieval and CompuServe) more powerful and easier to use.
Earlier i used the printed book as an example of a medium with which we are manifestly familiar; the reason for our familiarity is that the structure and conventions of books have been evolving for centuries. On-line databases have been in use for little more than a decade, and it is only in the last two or three years that large numbers of untrained users have started accessing them. Consequently, the learning curve for everyone—system operators, information providers, and end users—is particularly steep. There is still much to be learned about how users interact with electronic information utilities, what kinds of displays are best, what accessing protocols and commands are most effective and easy to learn, and what information is most appropriate.
Enlarging the Database.
The electronic edition of the AAE is already quite different from its printed parent. Updated twice a year instead of annually, it has no physical growth limitations, unlike the printed work. We intend to use this essentially unlimited capacity for growth: to respond directly to users’ needs; to reflect areas of strong current interest; to broaden the database so it is more appropriate to different age and interest levels; and to develop satellite databases designed to interact with the encyclopedia.
Responding to users’ needs: An electronic encyclopedia has a unique advantage over its print counterpart because it is possible to “capture” such key parts of the information transaction as search terms and usage time. Analyzing the captured data can reveal shortcomings, whether in the form of inadequate article headings or missing information. Such data also reveals areas of high and low interest—a useful guide for database growth.
Reflecting areas of strong current interest: Printed encyclopedias contain little information of transitory interest. It will be a long time before the Britannica has an article on Michael Jackson. This isn’t necessarily because encyclopedia editors disdain popular culture. The physical limitations of the printed work make it difficult and costly to insert large numbers of new articles each year. Space has to be found for each new article, usually at the expense of other articles. Further, an article of fleeting interest may create a difficult hole to fill when its importance diminishes.
This is not the case with an electronic edition, in which articles can be added to and deleted from the database with considerable ease. For example, coverage of the Olympic Games and athletes can grow in anticipation of this year’s meeting in Los Angeles. Next year the coverage can be reduced. An electronic encyclopedia can be a truly responsive, dynamic reference work.
Expanding for a broader audience: In its present form, the AAE spans a wide range of age and interest levels. As stated in its preface, the AAE is “for students from junior high school, high school, or college and for the inquisitive adult.” By expanding that base to include young children and advanced scholars, the resulting database will be several times larger than the printed encyclopedia and will be capable of responding appropriately to the user’s age and interests.
Satellite databases: Grolier has recently completed the first of a series of satellite database products designed to interact with, and be enhanced by, the electronic encyclopedia. Whiz-Quiz is a menu-driven educational game that directs the player to the AAE to find out more about a topic. We believe that children in particular will be compelled by this mechanism to explore the encyclopedia.
The User Interface.
Regardless of what shape or direction a database takes, the key to its use and value is the user interface. The user interacts with the electronic encyclopedia on several distinct levels: entry level: logging onto a system and getting to the database search level: entering a search term to locate a specific article (or group of articles) retrieval level: once the relevant article is located, finding and retrieving the required information manipulation level: getting the information in the form of a printout, writing words down directly from the screen, or simply remembering the facts exit level: leaving the database The first and last levels are entirely the province of the system’s operator and, in any event, are not an obstacle to most users. The search and retrieval levels, however, are areas of major concern because that is where the user works most closely with the system. The information-manipulation level will become increasingly important as software is written to take full advantage of encyclopedic databases.
The best way to analyze potential improvements at the search level is to return to the book metaphor. As an access device, a book is very forgiving. When you look something up in an index, you usually don’t need to know the exact spelling to locate it. Likewise, you sometimes use a dictionary because you can’t spell a word but have no problem locating it.
Databases are not so forgiving. A misspelled search term, no matter how close to the correct word, cannot be used to locate the required article. Some systems attempt to overcome this by providing a function called truncation. On Dow Jones News/Retrieval, for example, all you have to enter for an article on Zbigniew Brzezinski is “BRZ—a nice feature, but not the complete solution. The problem isn’t just misspelling; children in particular tend to use plurals for certain common nouns: cats, dogs, trees, dinosaurs, etc. This is not a problem in a printed reference work; however, when entered on a videotex system, the search terms will fail to match the exact article titles, which are singular.
First-time users, especially children, make repeated errors when entering search terms. Analysis of the search terms for one of the videotex services reveals that about one-third of all terms failed to locate an article. In approximately 90 percent of those cases, the information existed but errors (misspellings, use of plurals, incorrect positioning of names) prevented the user from finding it, at least on the first try.
Clearly, the unforgiving nature of search-term entry on videotex systems is a frustrating inadequacy that can be improved by the system operators. At the same time, the information provider has a responsibility. Other aids to access are required. Current videotex systems allow only keyword access to article headings. There is no on-line index, and today’s videotex systems do not have the full text-indexing capabilities of BRS and Dialog. Clearly, the specific entry headings need to be broadened so that the same information is available via several different search terms. An on-line index would broaden access still further, especially when combined with a thesaurus function.
Free text systems are not restricted to keyword access. Rather, the user can focus his search language to a highly specific degree, examining the body of knowledge with precision. The price of that precision is a high degree of practice and skill.
In the long term, both keyword and free text access to large databases probably will give way to search languages with a high degree of artificial intelligence (AI). At present, when you search for information in an encyclopedia, particularly on videotex systems, you have to think about its likely location. You cannot interrogate the database, but this is exactly what you should be able to do, posing such questions as: Who wrote The Grapes of Wrath? How many Nobel Prize winners went to Harvard? Where do icebergs come from?
Answers to all these questions can be found eventually with current systems, but a fully developed database incorporating AI search techniques would take you directly to the sources.
Having located an article, the user begins to read it. The “window” into the encyclopedia’s massive database is a television or monitor. The text display (depending on the service and the end-user’s hardware) varies from 16 lines by 32 characters per line (approximately 85 words) to 2 5 lines by 80 characters per line (approximately 330 words). By contrast, the printed AAE contains 1500 words per page, and pages can be viewed two at a time. Clearly, current video-display technologies are capable of only the most myopic view of a large text database, which is why it is all the more important to be able to rapidly shift the view, to be able to browse and move around in an article quickly and easily.
But there is a need for other orientation tool§, such as sequential numbering of article pages (which Dow Jones News/Retrieval has) as well as individual numbering of pages (which CompuServe has).
A recent study of a group of eighth-graders’ use of the videotex AAE produced some interesting findings. While the students searched for articles and moved around in them with varying degrees of proficiency, they confined their activities to finding information rather than using it. They actually read and manipulated the information later as printouts, which could be studied at leisure, marked up, and incorporated into their research projects. In fact, I suspect that many of our users who have access to a printer do their serious reading in ink-on-paper form.
This doesn’t mean that no one reads text from the screen. Graphics-oriented videotex systems, such as Viewtron, are based on the assumption that subscribers will read from the screen. This is fine for news summaries. But the real utility of an electronic encyclopedia won’t be realized until people can access, manipulate, and reorganize significant amounts of information electronically using such powerful information tools as word processors, database managers, and graphics programs.
Electronic Knowledge Land.
Grolier is working on some of the refinements I have been describing. We believe that, having freed encyclopedia information from the artificial constraints of the alphabet and the physical constraints of the book, we should be able to reshape and reorganize that information. We want to put it to new uses. We want to create a reference tool that can interact with other information tools. Additionally, we’re trying to build a conceptual framework—an outline of knowledge—for intellectual pursuit and stimulation. At present, this new “knowledge land” is largely uncharted, although major landmarks are known. We hope that videotex systems will have the navigational tools to explore it fully, and that software producers will have created the manipulation tools to exploit it fully.
A Videodisc Encyclopedia.
The videodisc is another interactive medium that we believe is applicable to encyclopedia information. The ability to randomly access any frame, combined with the disc’s dense storage capacity (54,000 frames per side on a laser disc) and its inherent audiovisual properties, make it a particularly powerful publishing medium. As part of a joint venture with Long- man, a British publisher, Grolier recently produced a pilot disc. The pilot was developed as a test vehicle to determine how the organization, content, and audiovisual treatment of encyclopedia material might best be accomplished.
Long before the pilot went into production, we had concluded that we would need a lot of discs to encompass all the information contained in a general encyclopedia. This led us to ask ourselves how each disc should be organized so that it could be both a stand-alone information resource and a part of an integrated series. We decided to organize each disc around a specific theme or subject area. The pilot is part of what will eventually be a two-sided disc devoted to the human body (see photos 2a through 2c).
Each thematic videodisc will be a self-contained information resource. The discs will not attempt to be the equivalent of a printed reference work. Rather, each disc will “illuminate” knowledge areas, conveying through audiovisual means only the essence of a subject.
Designed for use with a standard consumer laser videodisc player under normal keypad control, the discs will become considerably more versatile resources under microcomputer control. While the number of combined microcomputer/videodisc applications has increased substantially in the last two years—applications that include training, point of purchase, education, and games—there are few truly “generic” discs for which software can be written.
Grolier is developing two electronic databases, one in text form and one in audiovisual form. These two databases are being developed separately so that each can take advantage of the separately developing markets for on-line / videotex and videodisc products. But both databases will ultimately be brought together (although whether through telecommunications or local mass storage is yet to be determined). The result should be an innovative informational/educational resource: an encyclopedia that is appropriate to the media and appropriate to the times.
An Ideal Video Peripheral by Mark Dahmke
As a software consultant, my major complaint with most of the popular videodisc players is that they communicate with computers very poorly. Typically, the videodisc player is treated as a printer or a plotter; the user has to deal with commands that may or may not be ASCII (American National Standard Code for Information Interchange) format and may or may not be logical and consistent.
The Discovision (now Pioneer) model 7820 had a command set that looked like a selection of random numbers. The codes to send the numerals 0 through 9 were: 3F. 0F, 8F. 4F. 2F. AF. 6F. 1F, 9F, and 5F. in that order. In addition, the 7820 had an IEEE-488 external interface that wasn’t compatible with most microcomputers. In an attempted remedy. Discovision built a serial converter box to change the IEEE-488 protocol to and from RS-232C levels. What they came up with was a protocol converter with a 1-byte buffer that could easily be overrun, erasing the last command before it could get to the player.
Even if the translation and protocol conversion problems are ironed out eventually, a programmer is still faced with a stiff challenge in trying to get the status and frame number back from the player. Some players won’t give out this information at all. Ones that do return strangely encoded bytes that take many instructions to untangle. On some players the frame number comes back as a 2-byte integer. on another it comes back as four ASCII digits in hexadecimal, and on still another it shows up as five-decimal ASCII digits. Any software expected to run on more than one model of videodisc player has to account for all of these differences.
Timing seems to be the worst problem with interfaces. Data sent to the player at serial-port speeds just can’t control a fast videodisc player in the manner required by modern interactive applications. Some new players offer parallel ports, but many computers (e.g.. the IBM Personal Computer) don’t support full bidirectional interfaces. IBM claims that its Centronics port is “parallel input and output.” However, if you check the circuit diagram, you will see that it isn’t. It is wired so that reading the port returns only what was last sent.
Newer videodisc players operate at floppy-disk and, in some cases, hard-disk speeds. Some have worst-case access times of 2 to 3 seconds. Within a year or two, I expect to see write-once, multiple-read videodiscs with interfaces to let them be used as archives. (Some current videodiscs can hold gigabytes of data.) For this to work, however, the interface will have to be smart enough to recover the stored data and fast enough to return it to main memory at magnetic-disk speeds. This technique can work, as shown by the fact that it is already being used in several hard-disk backup systems for videotape recording equipment. In these disk-to-tape systems, the data from the disk is recorded redundantly in the scan lines of a National “television System Committee (NTSC) signal, which is then recorded on videotape. While this prac- tice could easily be transferred to videodisc hardware, much of the videodisc would be wasted and not used to its full potential. The developing direct-digital recording techniques will remedy this problem by maximizing use of the disc recording surface.
Loading software into a personal computer from a videodisc as if it were a floppy disk would greatly enhance educational applications. For example, audiovisual and computer-graphics course material (all orchestrated by an authoring language) could be combined and loaded into a personal computer from the first part of a videodisc while just the audiovisual portion is stored separately on the remainder of the videodisc. A development system would consist of the videodisc player and other end-product hardware, but the graphics and curriculum-specific data, or “courseware.” would be developed on attached floppy-disk or hard-disk systems.
Figure 1 shows one possible hardware configuration for a first-generation intelligent player. The main feature of the design is the videodisc interface adapter, which would plug into an expansion slot on the microcomputer. The interface adapter gives the programmer tight control over the timing of the player and also controls the video overlay circuit.
As digital television and audio reproduction become affordable and popular (I estimate that this will take five to seven years), we’ll be able to define the formats that will let personal computers store and retrieve video images and sound. We’ll be able to create high-resolution computer graphics and synthesized music on personal computers and write it onto a write-once videodisc peripheral. We’ll then be able to play it back through digital television sets. Alternately, digital television images could be recorded from TV sets onto a videodisc and then retrieved. displayed, or processed on personal computers.
Figure 2 shows a second-generation interface built around digital television. As 32-bit processors become faster, and memory bandwidth greater, it will be possible to directly manipulate high-resolution images that come from the videodisc or are created directly by the microcomputer. The video output from the TV camera can be routed to a digital television for viewing, or the output can be held in the graphics frame buffer for further modification and processing.
Mark Dahmke. a contributing editor for BYTE, is a software consultant and heads MCD Consulting Inc. He can be contacted at POB 80266. Lincoln. NE 68501.