CS99I Freshman Seminar

Traveling the Information Highways: Maps, Encounters, and Directions

©Gio Wiederhold and CS99I students, Stanford University, 1998.

This chapter will be augmented during this course for benefit of others course participants as well as for outside readers. Contributors will sign their additions.
Background references are available and are cited when appropriate.

Introduction

Gio Wiederhold

Master on Earth.
Draft 27 Nov. 1993, converted to HTML 29 Sep. 1997, updated 2,9,11,13 Jan, 7 Feb 1998. Syntactic update 23 Dec. 1999
Next chapter: The Internet

[© New Yorker Magazine]
Traveler, there is no path, paths are made by walking [Antonio Machado]

INTRO.Introduction

The purpose of this material is to provide a map to guide the traveler on the emerging information highways. Along these highways nearly the entire world can be reached, so that this guide cannot go very deeply into any specific topic. However, in contrast with more specialized guides, all topics are presented with their interactions and interconnections, so that the traveler can make decision which road to pursue and which off-ramp to use to get into the local neighborhoods and imbued in the local atmosphere.

Highways

Figure Highways: The Analogy of Transportation and Information Highways (figure on-line).

We will refer to this work as a book, since we are organizing it into chapters. However, crosslinks both with this book and to outside resources will be liberally used. The intent is to have an Internet book, about the Internet, on the Internet, and further exploiting the Internet, as the Internet develops. To accomodate the needed flexibility we will use names for chapters and sections, rather than a traditional, pre-determined numbering.

Since information is an abstract concept, we will use a popular analogy, as shown in Fig. highways. The highways represent the connections, implemented in the digital world by high- and low capacity cables, radio and optical transmissions. Along the nation's highways move people and goods, using a variety of vehicles appropriate to distance, the volume, and size and type of goods. These vehicles and their loads provide the analogy for the data and information to be moved. Armored trucks may be needed to move money securely. Along the highways are our mines, farms, and warehouses. Computer systems similarily collect from data resources and store raw data on their tapes and disks. At intermediate points goods are weighed, inspected, and approved for distribution. Data must often be checked and validated against other observations. Some goods and data can go stale, although spoiled does not smell. Factories take raw materials from multiple sources, combine it with output of other factories, to make products that others will want to buy. Service-oriented computer systems take data from multiple sources, and prepare it for other systems, until it is suitable for information consumers in form and content. The businesses along the on- and off-ramps come in all kind of sizes, and some are likely to be transient, while others are long-lived.

All these activities depend on having adequate highways. The nation's highways are never completed, there is always construction going on. Similarily, we will never be able to design and build the perfect information highways, which means that our data interchanges must be adaptable, so that progress can continue. Periodic traffic jams will also occur, because we will never have perfect building plans, nor the means to execute them all in time. Any analogy has its limits, and we will point out when the limits of the highway and goods analogy are reached.

!!here:scaling to ships, via composition of containers = truck/RR sizes>

INTRO.History

To understand one's surroundings when traveling, one needs some sense of history. A fair fraction of this book is concerned with the history of the technology that created todays information highways and the structures that we can enter along them. Every chapter since has a section on History, especially the chapters on the INTERNET for communications and on the supporting UBIquitous computing hardware systems.

Students at Stanford have the advantage of being able to view the Computer History Exhibits, distributed over 6 floors of the Gates building, we plan to put pictures of all exhibited artifacts on the web. Software is harder to display, and here the history sections in the chapters must help.

Definitions and References

A great deal of definitional material is provided with the history sections, and many technological concepts are described. The major contribution of this work might well be the technological definitions, which are presented to be both easy to grasp and yet be technically correct.

They are being summarized in a GLOSSARY. Since the definitions always appear in context, the glossary is an important part of this book, which enables its use as a reference work as well. The glossary replaces the traditional index.

REFERENCES to the literature focus on books which provide more detail; with the breadth of material covered a comprehensive bibliography would be extremely voluminous. Keeping up with advances in technology is equally frustrating. We hope to be able to maintain this guide on an electronic library, but current

copyright mechanisms to not provide adequate protection to assure that authors will receive proper fees, as discussed in Chapter SECURITY.

Maintenance

Originally this material was intended to be single-authored book. However, it has been impossible to keep up with the rapid developments on the Internet, the highways are growing faster than the mapmakers can provide the needed guidance.

The plan is hence to use this book as a dynamic resource for teaching, and for documeting what teacher and students have learned in a course. We hope that the layout of the book can survive for some time, while new roads, on-and off-ramps are being built.

INTRO.History.institutions

The information highways cannot be understood without knowing the organizations who built them, are maintaining them, or depend on them for their operations. We introduce many of them in their contexts, and also index them. Understanding their objectives will help those who wish to cooperate with them, sell their services to them, or purchase services from them.

In the chapters of the book we describe some of the major users of the digital highways. In Sections INTRO.people we introduce tourists and wanderers (Lurkers in [Denning]), people who travel to learn, to experience, and to browse though the the neighborhoods along the highways. Serious researchers will use libraries, subsribe to journals, purchase books, and become authors themselves, as described in Chap. library. Publishers play a critical role at this level. More generally, the new technologies will affect entertainment and education.

Important for the economy are the uses of these technologies in MANUFACTURING, and more general ELECTRONIC COMMERCE. Information is crucial for planning and decision-making. Geographic information has an important role in identifying where one is headed. A topic of concern to most branches of government and individuals is HEALTH care.

INTRO.Functions.applications

The main portion of this book introduces applications for the future information superhighways. Major categories were listed already in the section on< A HREF="#HISTORY">History. The maps and directions in this book indicate then as well what is to found when one takes the off-ramps, and explores the countryside. Since the digital highways are still being built, much local activity has not yet been affected by them, but many businesses located away from the highways are rightfully concerned.

These applications depend on common services. Interspersed with the application chapters we plan chapters dealing with DATABASES that document the past and SIMULATIONS to predict the future. Databases capture the experience of the past and simulations help understand the future. As such these technologies are critical to the goals of the information infrastructure, and support the concept of learning and education wich is crucial to its objectives.

Finally we plan to include material that consider the problems and solutions dealing with the problems of the heterogenity of the world through MEDIATION, the PROGRAMMING and assembly of the software components that are the building blocks of the digital highways and its surroundings, and the SECURITY afforded to travelers and inhabitants.

The initial chapter must focus on the technology of the Internet. And, to finish, we will project the FUTURE with a conclusion.

INTRO.People

The greatest joy when traveling is encountering interesting people. People build the institutions, formulate the pathways for interactions, and communicate with a bandwidth not achieved by any electronic method. We present a brief biography in each chapter as a Section a biography. Most of the people are still active, and we hope that they will not take offense at being included.

Types of people on the Internet

People are in the end the providers and users of Internet technology and its contents. To understand the fuctions of the Internet we have to recognize the roles that people can play. These roles are not narrowly transcribed, and individuals can assume multiple roles, simultaneously or at different times.

• System builders
• Authors of content
• Distributors
• Readers
• Planners
• Customers
• Lurkers

INTRO.People.motivation

Educated users will also be better be able to make committments, both of their time and their finances. If the book provides the motivation to get involved and learn about the opportunities and eventually exploit them, it has achieved its function.

INTRO.People.neighborhoods

INTRO.Functions

We have given each chapter (say, X) a similar layout. After a short introduction (Sections X.Intro) we cover the relevant history (Sections X.History) in some detail, as done in general above. We then briefly identify the participants (Sections X.People).

The main body of each chapter (Sections X.Functions) is devoted to the functions that comprise the topic. Many systems provide hundreds of functions, but their essence is captured by a few basic ones. These few will be the focus of the presentation. How more complex functions can be composed out of simple functions will be a secondary concern throughout.

A tertiary class of functions encountered inpractice are meta-functions, those that document, install, or help manage the primary functions. These will only be covered when they are crucial and common, since meta-functions tend to differ widely among system implementatons. In the end, a user of a systems has to be willing to go to a manual provided by the software or hardware vendor. This book cannot serve that particular role.

Format of the Chapters

Since we expect that many people will contribute and modify this work over time we have organized this virtual book into three consistent levels, with a fourth level that is more flexible. This chapter describes the contents, here we summarize the typography for the headers, formatting, and HTML naming conventions.

1. Chapters have titles at level 1, and are typed in upper-case, for example INTRO.
   All contain similar sections.
   They are managed as distinct files, with lower-case file names, for example "intro.html".
2. Sections have titles at level 2, and are typed capitalized; the Chapter title is prefixed, to allow easy identification, for example INTRO.Functions.
   They contain subsections of variable naming and contents.
   All sections are named for crossreferencing (in Uppercase), for example NAME="FUNCTIONS" for this section.
3. Subsections have titles at levlel 3, and are typed in lower-case; again the Chapter and Section title is prefixed, to allow easy identification, for example INTRO.Functions.format.
   Subsections are normally managed and assigned as a unit.
   Subsections are also named (Uppercase) for external reference, for example NAME="FORMAT" for this subsection. When modfified the author and date should be appended.
4. Subsubsections are optionally used, with Headers at level 4, captialized but without prefixes, for example Notations.
   Their content is dependent on the surrounding text.
   The can be named (Uppercase) if they are to be referenced.
5. Figures are named, rather than numbered, for flexibility.
   Figures and external objects are seperate files in the figures subdirectory, and are named in lower case.
   Cross references to figures are named in lower case.
6. References appear in square brackets.
   The full citation will all appear in the refs.html file, and named by their code, as [Lehnert97].

Notations

INTRO.Technology

The technology required to carry out the functions will be discussed in Sections X.technology in a fair amount of detail. In the initial two chapters, the Sections INTRO.Technology and INTERNET.Technology focus on the infrastructure, the highways themselves, and hence are technologically oriented. The technical material presented should suffice for two objectives. First, a reader who needs or wishes to delve further ito the topic is enabled to select and assimilate further specifics. Second, a reader who wishes to use a system embodying the technology, can form an adequate abstract model to to mentally manage its capabilities and its limitations, and become an informed consumer. There is no magic involved in these topics. Furthermore, while the whole composition of the network is indeed complex, it is composed of fairly simple parts. Observe that if systems are not methodically composed of simple parts, they would never work reliably.

INTRO.Alternatives

For each technology chosen other alternatives are possible. These are presented for the topic of each chapter in a subsequent section X.alternatives. The choice of primary versus alternative approaches i s based on pragmatics: actual use and successes that have been achieved with it. Discussion of alternatives to primary technology broadens the material beyond the purely descriptive information which dominates corrent literature about the Internet.

Often a technology which seemed better has failed to be successful. In many cases we can identify plausible reasons for such failures. We hope that analysis of failures can provide insight in how to avoid similar pitfalls in the future. We should be able to learn more from failures than from successes, since there are more of them, even though less is published about failures than successes. Note that much literature precedes implementations, so that we read much about hoped-for successes that eventually did not pan out.

INTRO.Conclusion

At the end of each chapter we provide some indication of where the topic is likely to be headed. These are obviously personal assessments, and can easily be invalidated. The book should not be judged by those assessments; giving directions to strangers on a highway is always a risky business, and even more so if the trip will take many years to complete.

INTRO.Lists

Lists are handy as references, but also boring. As Umberto Ecco's protagonist (Sean Connery in the 1986 movie by Annaud) states in the 'Name of the Rose', when trying to identify the villain: "There is nothing more wonderful than a list, and we could go on and on, but now we have to go out and investigate the world">. At the end of a chapter (Section X.lists) we provide a list of the items that the chapter focused on. These lists give a useful summary, but will never be comprehensive.

INTRO.Technology

We introduce now concepts of computing and communication at high level. for readers with experience in computing nothing novel will appear here, but the introduction will assure that all common concepts and terms used later will have been encontered and defined.

INTRO.Technology.architecture

A computing systems is layered !see material from s1dbd. reword to use traveling paradigm

Figure INTRO.layers: Source layers picture from dbd (not yet on-line.

INTRO.Technology.nets

Figure INTRO.nets (not yet on-line) Users with dumb terminals, personal computers (periodic connection) workstations, LANs. WANs (with HPCC), mainframes, mini-computers, databases.

INTRO.Technology.communication

! not yet written

modem

Figure INTRO.communication (not yet on-line): Linkage from workstations and portables, on analog with modems, digital phone lines, LANs. WANs

INTRO.Technology.operating systems

Operating systems control the computer hardware. The five major functions being provided by an operating system all are related to resource alloaction, namely figuring out who gets to use what part of the computer when. We also indicate the metrics used for the five functions.

1. Starting and stopping operations, or better trying to prevent that the system ever stops. When operating systems fail however, the machine may have to forcibly stopped and rebooted. All active work, not safely placed on persistent storage, is lost. A computer hence has up-time, and down-time The average interval between uptimes is called Mean-Time-Between-Failures (MBTF). Small MBTFs frustrate users and cause losses beyond the down-time in reconstructing ones work.
2. Allocation of memory, so that programs and data do not conflict with each other. All active work is done out of memory, and if multple tasks are active, then each of them needs memory. When memory is inadquate, many operating systems can temporarily move tasks or pages of task into storage, and page then back in, when needed. Some tasks are associated with users, others may be system tasks, for instance the accounting program, or the program that checks if a new user wants services. The quantityof memory available in a computer is measured in Megabytes from a few in modern home computer, to a few thousand in big institutional machines.
3. Allocation of processors among users' and system tasks is the central function in an operating system. This kernel function determines how much work gets done for whom. To be eligble for processor cycles a task should be set up in memory, have data ready to be processed, and then have a higher priority than other ready tasks. The speed of a computer is measured in Megaops, namely millions of primitive operations per second. The range is from less than a Megaop for home computers to thousands for large machines. This measurement however is not that precise, because the definition and utility og primitive operations varies. For scientific work sometimes Megaflops are used, counting numeric floating-point operations.
4. Managing persistent storage, so that established files will remain available overthe long term. Both programs, supplied with the computer, programs obtained by users, and data generated or obtained by users are kept on persistent storage. The files also have to be named, for retrieval, and identified with their owner. File storage is also measured in Megabytes, but here the variability is greater than for memory. Modest home computers may have 20 Mbytes on-line, more storage can be kept on disks that are stored nearby, or better, protected fom damage in a safe place. Institutional computers can have a million Mbytes, i.e. Terabytes of on-line storage.
5. Manage all other input and output devices, as keyboards, screens, printers, scanners, cameras, communication linkages, and the like. Since these tend to vary even a among similar machines owned by different people, it is wise to keep input-output functions outside of the * kernel of the operating systems. Communication speed, to trap the unwary, is typically listed as Megabits/second, requiring a division by 8 to compare it with say storage in Megabytes. Communication speed for a home computer on a telephone may be as low as 1200 baud, or 0.001 200 Megabits/second, but a local access network (LAN) in a business will operate at 10Mbits/second. Printers and keyboards are quite slow, a fast typist may reach 120 baud for a short time.

We will not further present the technology of operating systems, but note that types of operating system are strongly related to the management mode of a computer system and its enviroment. That topic is exOApanded on in a Chapter on Ubiquitous Computing. A programmer, trying to make the hardware something the novel, may want to change the operating system. But in a computer serving many people any change that improves the system for some is likely to hurt others, at least until changes settle down. This means that few people, often labelled * superusers, have the priviledge of changing operating systems. But if you operate your machine, then you can be your own superuser; you can only hurt yourself.

Other people see the hardware and the operationg system as a whole. If different types of computers have the same operating system they may act nearly identical, if the operating systems on the same machine is replaced, it may change so radically that no prior work is usable.

INTRO.Alternatives

Since this first chapter does not cover a specific technology or application area, it is not clear what the alternative to an introduction are.

There are of course many alternatives to learning about the web. All of them should involve actual use, but there is more material being added daily then any sigle person can read, so that any book should supply directions and a roadmap.

The concept of directions: How to find something and having a roadmap, which gives one the abilty to select one's own path are alternatives as well. This book is intended to be more of a roadmap then a set of directions to follow when traveling on the information highway.

For readers who start reading the conclusion of a chapter and the proceed forwards, let us remind them that this to be a work of many authors, since the highways, and hence the maps to it can never be complete,

INTRO.Conclusion

Even though this book provides a fairly high-level overview, many technical topics are introduced, topics that at one time were far beyond the interest and need of most individuals. In the early 1960, when computer used was in its infancy, but growing rapidly, extrapolations of the growth in the programming profession indicated that by 1995 there would be as many programmers in the United States as adults. That extrapolation was viewed as clearly ridiculous, what about all the other professions? In retrospect, the prediction has become true, but not in sense seen in in 1965. Anyone who uses a spreadsheet is a programmer, maniging such computations required specialist expertise in the 1960ties. Even obtaining information from the web initiates operations that once were so complex that they could be performed only by information system analysts. The use of word-processors, VCRs, even microwave ovens involves instructing computers what to do. It won't be long before most of us will be information scientists as well.

The purpose of obtaining information is to help us make better decisions. having information enables us to make the best choices, weighing benefits, costs, and risks. Balancing these factors remains a human !task, since the valuation of dissimilar factors cannot be automated. Only when values are assigned to the factors presented for the alternatives can we delegate the making of decisions to a computer. In a recent survey 85% of the people queried felt that they did not need more information.. When we use the abstract term * decision maker we are likely to think of captains of industry, of generals, or of millionaire investors. But in practice we are all decsion makers, in selecting purchases, in balancing work and health, when planning vacations, or switching among television channels. For information to be relevant however we must have choices, in goods to be purchased, in selecting sports and healthcare choices, in destinations for travel, and in entertainment. There is hence an interplay between having a free society and liing in an information society.

INTRO.biography

Joshua Lederberg.

Since using computers beneficially is the prime motivation for establishing the information highways we will start the biographies with a brief history of a person who always focused on his profession, Genetics, but in the process used and motivated computing and communication facilities. Professor Joshua Lederberg !BACKGROUND>. !get his Nobel lecture>. In 19!xx> he assumed the post of professor and chairman of the Stanford Department of Genetics, !shorlly after it, and the entire Medical school moved from San Francisco to the main campus near Palo Alto, in order to achive closer cooperation with the science departments of Stanford University. In 1964 a computer science department was established at Stanford, led by Prof. George Forsythe. New faculty members, Profs. John McCarthy, the inventor of the language LISP, used widely for applications in Artificial Intelligence (AI), and Prof. Edward Feigenbaum, whose prior work was in Cognition, another topic in AI, were especially relevant to Prof. Lederberg's interest. !what then> for In 1964 he started using one of the largest computers in the U.S. over a remote phone line between Northern and Southern California. The * IBM AN-FSQ32 was designed to control the Air Defense System of the U.S., but was never actually placed into service. However, computer specialists at System Development Corporation (SDC) installed a * LISP system on that machine, and its large memory (xxK) permitted larger programs to be run than on computers available at Stanford University. !led to xxx machine at Livermore , an early supercomputer > !* ACME> !* SUMEX-AIM> !email article> !Rockefeller University> !* Collabratories> !recent>.

!Clark Weissman was working on Adept in 360 pr !contact Kameny> >

INTRO.lists

SERVICE PROVIDERS ON THE INTERNET

This list was last updated in 1995. It has grown manyfold since. In addition to adding more services, we also need better descriptions of the services being added, and their value. Organizations providing network services are listed in Chap. INTERNET.Networks.

Infrastructure and technical support are listed in Chap.INTERNET.lists.

Chapters Planned for Traveling the Information Highways

Next chapter: The Internet
oList of all Chapters.
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