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Wide Area Information Server Concepts
Brewster Kahle
Thinking Machines
11/3/89
Version 4, Draft
Wide Area Information Servers answer questions over a network feeding
information into personal workstations or other servers. As personal
workstations become sophisticated computers, much of the role of finding,
selecting, and presenting can be done locally to tailor to the users
interests and preferences. This paper describes how current technology can
be used to open a market of information services that will allow user's
workstation to act as librarian and information collection agent from a
large number of sources. These ideas form the foundation of a joint
project between Apple Computer, Thinking Machines, and Dow Jones. This
document is intended for those that are interested in the theoretical
concepts and implications of a broad-based information system.
The paper is broken up in three parts corresponding to the three components
of the system: the user workstation, the servers, and the protocol that
connects them. Whereas a workstation can act as a server, and a server can
request information from other servers, it is useful to break up the
functionality into client and server roles. A final section in the
appendix outlines related systems.
Ideas for this have come from Charlie Bedard, Franklin Davis, Tom
Erlickson, Carl Feynman, Danny Hillis, the Seeker group, Jim Salem, Gitta
Salomon, Dave Smith, Steve Smith, Craig Stanfill, and others. I am acting
as scribe. Comments are welcome (brewster@think.com).
Table of Contents
I. Introduction
II. The Workstation's Role in WAIS
A. Accessing Documents with Content Navigation
B. Dynamic Folders Find Information for the User
C. Using Information Servers
D. Other User Interface Possibilities
E. Advantages of Remote and Local Filtering
F. Local Caching of Documents
G. Local Scoring of Competing Servers
H. Budgeting the User's Time and Money
III. The Server's Role in WAIS
A. Probing Information Servers
B. Examples of Information Servers
C. Navigating through the "Directory of Services"
D. Servers that Rate other Servers
E. The Role of Editors
F. Markets and Hierarchies: Using Silicon Valley
G. How Server Companies Can Make Money
IV. The Protocol's Role in WAIS
A. Open Protocols Promotes Wider Acceptance
B. Hardware Independence
C. Protecting the User's Privacy
V. Conclusion: Why WAIS will Change the World
VI. Related Documents
VII. Appendix: Comparisons to Existing Systems
A. Compuserve
B. Minitel
C. NetLib
D. Switzerland system
E. Lotus and NeXT text system
F. Information Brokers
G. Hypertext
I. Introduction
Distributing knowledge was first done with human memory and oral tradition,
later by manuscript, and then by paper books. While paper distribution is
still efficient distribution mechanism for some information, electronic
transmission makes sense for other. This project attempts to install an
electronic "backbone" for distribution of information. Some information is
already distributed electronically whether it is printed before it is
consumed or not. This project attempts to make electronic networks the
distribution technique for more types of information by exploiting new
technology and standardizing on an information interchange protocol.
The problems that are being addressed in the design of this system include
human interface issues, merging of information of many sources, finding
applicable sources of information, and setting up a framework for the rapid
proliferation of information servers. Accessing private, group, and public
information with one user model implemented on personal workstations is
attempted to allow users access to many sources without learning
specialized commands. A system for finding information in the sea of
possible sources without asking every question of every source can be
accomplished by searching descriptions of sources and selecting the sources
by hand.
An open protocol for connecting user interfaces on workstations and server
computers is critical to the expansion of the available information
servers. The success of this system lies in a "critical mass" of users and
servers. This protocol, then, could be used on any electronic network from
digital networks to phone lines.
For the information owners to make their data available over a server, they
must be easy to start, inexpensive to operate, and profitable. One
possible approach would be to provide software at a low price that will
help those with information holdings to put their data on an electronic
network. The power of the current personal workstations is enough to
enable sophisticate information servicing capabilities. Charging for
services can be done in a number of ways that do not entail setting up
large billing operations. In this way, it is easy to set up, operate, and
charge for information services.
The key ideas that the WAIS system are that information services should be
easily and freely distributed, that the power of the current workstations
can provide sophisticated tools as servers and consumers, and that
electronic networks should be exploited to distribute information.
II. The Workstation's Role in WAIS
The personal workstation has grown to be a sophisticated computer that can
store hundreds of books worth of information, multiprocess, and communicate
over a variety of networks. The advanced capabilities of the workstation
are used to find appropriate information for the user by contacting,
probing, and negotiating with information servers. The explosion of
available information may change the way we use computers since the usual
approaches to information on workstations may not grow to make the new
information environment understandable. The proposed mechanism involves
finding information with one mechanism called "Content Navigation" whether
the data is local or remote, available immediately or over time. This
section details what a workstation might do to collect and present
information from a variety of sources.
A. Accessing Documents with Content Navigation
Currently, the common way to find a document (or file) is the "Finder" on
the Macintosh or most other machines. This tree structure requires the
user to remember where s/he has put each file. This approach works when a
user is familiar with the file organization. It is also computationally
efficient. To aid those that have forgotten the exact location many
systems have some way to locate files anywhere in the structure based on
the filename ("Find File" on the the Mac, and "find" on Unix machines).
The number of potential files increases as the disk space become less
expensive and networks let users access remote files. At some point, when
the number of files becomes large, this organization can become unwieldy
because of the amount the user has to remember. Another technique that is
currently popular is to augment documents with static HyperText links 1,2.
These links help users move through 500 Megabyte CD-ROMs of data without
being overwhelmed. HyperText systems allows the author to provide "paths"
through the document. The HyperCard system, from Apple, also has a simple
content searching mechanism that helps navigate without those links.
HyperText links give the author another tool to guide the user and augment
the capabilities of the file system.
A different technique that would allow access to a large collection of
documents based on document content and similarity can be called "Content
Navigation." With this tool, documents are retrieved by starting with a
question in English. A single line, or headline, would describe possible
documents that are appropriate. These documents can be viewed, or used to
further direct the search by asking for "more documents like that one".
Each document on the disk (or some other source) is then scored on how well
it answers the question and the top scoring documents are listed for the
user. Since full natural language processing is currently impossible, each
document type, be it and newspaper article or a spread sheet, must have
some simple measure to determine how relevant it is to the question asked.
For text documents a useful and powerful measure is to count the number of
words in common between the question and the text. This well known
technique of Information Retrieval1 can be augmented with different
weighting schemes for different words or constructions. Other types of
information might be retrieved with specific question formats.
Thus, documents can be found by asking the "navigator" for documents that
contain a set of words. Those documents that share the most words with the
question will come back at the top of the list (have the best "score"). In
this system the "answer" to a question is not a single document, rather it
is an ordered list of candidate documents.
Content navigation is not new; NeXT and Lotus have implemented systems for
personal computers,2 many text database systems on mini-computers, and the
DowQuest system using a super-computer. In general, there is no
standardization yet on how these systems should be queried and used.
B. Dynamic Folders Find Information for the User
Content navigation takes a question and returns an ordered list of possibly
relevant documents. The question can be further refined by giving feedback
as to how relevant the documents were. The results of a question can be
seen as cousin to the file folder in that it contains a list of documents.
In reality, the answers to a questions might not be a "copy" of a document,
but a "reference" or pointer to a document. These question and answer
sessions can be saved just like a file folder can be saved. Saving a
session also frees the machine to find answers when the user in not
looking. This capability becomes important when some of the questions take
time to answer because the data might be far away or difficult to answer.
This section discusses one way to think of a saved question: a Dynamic
Folder.
"Dynamic Folders" are a cross between a database query and a Macintosh
folder that can give us great power in defining questions and probing
databases. Text database queries respond with a list of pointers to "hit
articles", in the form of titles or headlines, that might interest the
user. At that point, the entire article can then be retrieved, if desired.
A Dynamic Folder, similarly, has a question that is used to retrieve
headlines. Further a Dynamic Folder can be saved and viewed later. Since
a folder is a also structure that holds documents so that they can be
viewed later, a Dynamic Folder is a folder that has a question associated
with it.. In that way a dynamic view acts like a database query in
collecting pointers to interesting documents and like a folder in that it
can be closed and opened at different times. A Dynamic Folder's question
or "charter" acts as instructions to an active agent as to what what should
be put in the folder. This charter gives the folder a mission to keep
itself full of appropriate pointers to files or documents. This charter
might be as simple as "all files on my personal disk that have a .c
suffix", or all mail received in the last day. In some circumstances, it
is important for a Dynamic Folder to contain pointers to a part of a file
rather than to an entire file. Treating parts of files as first class
documents is important in systems that group many independent documents in
one file, such often done with e-mail or news articles. In this way,
"documents" and "files" are slightly different.
A Dynamic Folder's contents will change when the charter has changed, at
fixed intervals, or when external events happen. The user interface should
indicate how current the folder is if it does not always appear up to date.
Ideally, when a user changes the charter of a Dynamic Folder, the contents
would reflect this instantly. This is possible for local searches and some
remote searches. Sometimes, however, changes in the available documents
can not be reflected immediately. This is the case when indexing the
contents of new files can take a while and is done in the background. Some
folders should be updated periodically to reflect new documents in remote
databases. For example, a folder that uses the New York Times should be
rechecked every day for new articles. Other updates to folders could be
done based on events happening such as a new document being stored on the
local disk. This could cause all appropriate folders to see if that file
is appropriate to add to the contents.
C. Using Information Servers
Information servers sit on a network and answer questions. A server,
whether local or remote, has some database that can be queried and
retrieved from. These servers can be easily accessed by a workstation over
a network with a standard protocol (see the Protocol section) using the
Content Navigation tool to state queries and the Dynamic Folders to hold
and coordinate the responses. In this way, a user's sources of information
can be seamlessly expanded past the contents of the workstation without an
extra conceptual burden on the user. Part of the "charter" of a Dynamic
Folder, then, is the servers that it should use. This combination of tools
extends the reach of the user while maintaining a consistent view of
information. The capabilities of the servers will be discussed more in the
server section, but it is important to see at this point that the
workstation can be negotiating with a large number of local and remote
servers.
D. Other User Interface Possibilities
The "Dynamic Folder" is just one way to portray the results of a question.
Other visual and aural possibilities have been suggested including draw
from newspapers, books, library shelves, and sound recordings. This
section touches on these possibilities.
Presenting information in newspaper format has been tried at the MIT Media
Lab (NewsPeek). This approach shows not only a one-line headline, but also
the writer, date, place, and first few paragraphs of the article. This
format expresses importance by the size of the headline typeface, the
organization of the articles on the page, and the amount of text include on
the first page. Advertisements also have a place in such a presentation.
Using a book or a loose-leaf binder metaphor has been explored by the
Hearst group at Apple. In this model, the inside flap of the book is used
to describe the charter of the book. A table of contents is the headlines
that can be retrieved. Further, the book can have sections to it separated
by tabs. An index fits naturally into this model. The Dynamic Folder is a
version of this idea.
Borrowing from e-mail programs, listing the possibilities in order of
importance has been the technique used by Thinking Machines and NeXT for
displaying candidates. Selecting an article brought the text to another
window. This interface style allows the user to mark "good" documents to
further refine the question. This approach is closely related to the
Babyl, Rmail, and Zmail mail handler programs(ref?).
Showing the source of documents geographically was suggested by Tom
Erickson of Apple. In this approach, a world map can be used to show areas
of interest. This might be a good way to initiate browsing if geographical
relevance is an important factor to the user. The number of articles
concerning or originating from an area can be displayed conveniently.
Presenting documents like books on a shelf is a familiar metaphor to
librarians. Information about the age of the book, how frequently it has
been used, its size, if it is a picture book or monograph or pamphlet, when
it was published (by the age of the font) are easily gathered with this
presentation. Grabbing a book and looking at it, or looking on the shelves
close by are natural reactions in this metaphor. I do not know of any
attempts to display information in this way.
Generating a recording of a person reading the top articles can be useful
for commuters. With simple skip forward and back capabilities, this might
be an effective way to deliver a custom newspaper to someone driving a car.
This ideally would be done with a CD player, but a cassette could be used.
The Dynamic Folder is just one possible presentation idea. This area will
be an interesting area for research and prototypes.
E. Advantages of Remote and Local Filtering
When a user subscribes to a remote server, the user can get a complete copy
of the database unfiltered, or can instruct the server to filter the
documents remotely. Printed newspapers are delivered whole whether all of
it is relevant or not. With electronic distribution, one can imagine a
user asking for all sports articles but not the business articles. A query
is a form of filter that works at the server. A broad query will retrieve
a large number of documents that can be further filtered on the personal
workstation. The system and protocols can handle filtering at either or
both ends.
Local filtering can done by the content navigation on the local disk after
the documents have been retrieved. The quality of this filtering will
depend on the quality of the content navigator on the local workstation.
The filtering might be able to use knowledge about the user that is
impractical to deliver to a server. Local filtering gives the user the
most flexibility, but it could entail too much communication or too much
disk space. How much filtering will be done on the local workstation has
tradeoffs that must be made on a server-by-server basis. If the filtering
is done locally, then the workstation might have a subscription to a server
that periodically retrieves the newest articles.
Remote filtering can reduce the communications bandwidth as well as
possibly offer better filtering. A server can have better filtering
capabilities because it can be database specific as opposed to the
workstation's navigator that must be quite general. Remote filtering, just
like an interactive query, in initiated by using a question.
As communications, storage, and local computation costs change relative to
each other, different filtering structures might make sense.
F. Local Caching of Documents
Documents that have been retrieved from a server are stored locally on the
personal workstation in a cache. A cache is a computer architecture term
meaning fast, short term storage that helps speed up access by remembering
commonly used entries. In this context, a cache would store documents that
the user has seen or might want to see so that access to those documents
would be faster and easier. A fundamental property of computer caches is
that the use of the cache only makes access faster rather than changing any
functionality. In certain circumstances, it might be useful to relax this
constraint, but this will be seen below. Most interactive queries will
only use the cache and local files because the cache will be up-to-date on
its information subscriptions. The cache is very important to make queries
interactive even though data may have come from remote servers.
The document cache would be stored locally but is shared between all
Dynamic Folders. In this way, an article retrieved for one reason could be
used in another folder without requiring two copies. A central repository
would have to be managed carefully to keep the most relevant articles but
not to overload the storage. A quota might be allocated to the cache, and
a cache manager would make decisions about what should stay and what should
go. Sometimes the user should be consulted, and other times it can be done
automatically. The cache manager should keep header information on how
each document in the cache such as: (1) what server the document came from,
(2) how big it is, (3) if it was looked at by the user, (4) when it was
retrieved, (5) what folders point to it, (6) if the user asked to keep it
permanently, (7) what the user thought about it , (8) how hard is it to
retrieve it again, (9) how to retrieve it again, if at all. If a document
has been deleted from the cache, but it is still being referenced by a
Dynamic Folder, the header information should be preserved enough to be
able to retrieve the document again. In this way, deleting a document is
not a catastrophe.
Since a cache can hold many of the articles seen by a user, the cache is
useful in answering retrieving documents based on "I read an article once
about..." (In a study of libraries users of scientific journals, about 60%
of the articles read were found by browsing, and about 30% were from
remembering that they saw it before and they wanted to know more).
Supporting this type of question is important for a WAIS interface. The
cache can help here by storing all the documents that the user has read.
If the cache can not store all of them then it can be instructed as to what
type of documents it should keep on hand.
G. Local Scoring of Competing Servers
Since a Dynamic Folder can get its data from many servers, it must merge
this data and present it in a meaningful way to the user. While servers
that rate other servers can help determine which server's answers should be
valued (see the ***ratings section), these servers only rate the server as
a whole and not the individual documents. Furthermore, the article could
be very good, just not appropriate to the question. One way to order the
responses presented to the user could be based on a "score" that is
assigned to each response by the server. Each server might, for instance,
judge the appropriateness of its response to the question on a scale of
1-10. These lists from multiple sources could be merged in that order
(weighted by the ratings of the servers) and presented to the user.
Unfortunately, since a server would want its data to be used, it has every
incentive to rate all articles with at 10. Thus, determining how much to
trust the server's scores will improve the selection of documents presented
to the user.
One possible solution to this problem is to have local scores for servers
to augment what the server says. Therefore, if a server always says "this
answer is worth 10" and the user never finds it useful, then the personal
workstation can lower the trustworthiness of that server's estimation of
itself. Saying 10 all the time is the equivalent to crying wolf; if it
does it too often, then users will stop listening. In such a scenario,
then, all responses from that server could be degraded by 30% before it is
used to merge in with the other database's responses. On the other hand,
other databases may underrate themselves and should be boosted. This local
scoring can be used to indicate a user's satisfaction with a database and
could be used by others to help in rating it. Further, this local score
could be used to determine if the server is worth subscribing to or keeping
its articles in the cache.
H. Budgeting the User's Time and Money
Since the users workstation will be spending the users money to contact
some servers, a system of accounting and budgeting must be installed so
that users get the most value for their money. The trade-offs of time and
money can be tricky to try to represent, so a simple system should be
attempted first. The underlying premise is that the computer knows how
much it cost to use different services. This can be easy if a service
charges for connect time. If a service is reached with a long distance
phone call, however this rate could be difficult. (Maybe a server should
be set up that knows how much the phone companies charge for different
calls.) Further, if a server charges based on the question, there must be
a way for the protocol for limiting the amount spent.
Some queries are going to be very important to happen quickly or they are
of no use. Working this into the interface can be tricky.
Ideas towards automatic budgeting are still quite primitive. They involve
global limits per month, or limits per Dynamic Folder, etc. Should the
workstation enforce the limits? Who can override the limits? We need
ideas on this one.
III. The Server's Role in WAIS
Servers sit on networks and answer questions. Successful servers will have
some expertise or service that others find useful whether it is primary
information, information about other servers, or a service. A file server,
a printer, and a human travel agent can all be viewed as forms of servers.
This section describes how servers might be used in a Wide Area Information
Servers system.
A. Probing Information Servers
Finding documents (or more generally, information) on one's personal disk
is important, but finding relevant information on remote systems would
extend the usefulness of personal computers. Currently, most remote
database accesses are not integrated with the workstation model using a
"glass terminal" interface which does not use the power of the workstation.
Some servers look like extensions of the file system and do integrate
naturally (such as Sun NFS and AppleShare) but do not provide ways
documents based on content. One of the major goals of the WAIS project is
to integrate wide area requests in a natural way with local area requests.
This section will describe how different information servers could be
integrated into this model.
Using the Dynamic Folder, the user creates lasting questions that can
collect answers over time from a variety of sources. The charter of a
Dynamic Folder includes what sources should be used, which might include
the local disk, local special purpose information servers (such as
dictionaries etc), AppleShare file servers, and remote databases or WAIS
(see the Examples of Information Servers section).
A wide area information server is a computer which provides information on
a particular theme to other computers. Servers sit on a network, such as
the phone system, the Internet, or X.25, accept connections from other
servers or users in order to answer questions in a standard format.
Each information server can be queried at the time the charter is updated,
or it can be periodically polled for new information. Newspaper servers,
for instance, should be polled to find new articles, while dictionary
servers should only be queried once because repeatedly asking the same
question is pointless. Thus, the user's workstation keeps information
about each server.
While a map, a spread sheet, an airline ticket, or music might be the
appropriate reply to a specific query, the initial question is stated in
English. A charter (or question) about "Beethoven's choral works" might
result in an article from the encyclopedia server, a schedule of concerts
from the newspaper server, and recordings from a music server. Depending
on the networks used, some responses might be impractical to retrieve, but
the architecture allows for any type of information exchange.
A Dynamic Folder can also be used as an information server to other
workstations. This simple form of server can enable others to share
information easily. This capability should be put into the user interface
to encourage people to exchange information. A Dynamic Folder could be
"exported" or made available to those that know about it, or "advertised"
by adding it to a directory of services. If it is entered into a directory
(which is just another information server) then an English description of
the folder should be included.
An information server is probed by putting it in the sources section of the
folder's charter. These servers can be varied in size, content, and
location. Using content navigation and Dynamic Folders we have an metaphor
for accessing many types of information servers.
B. Examples of Information Servers
Information servers, in the broadest sense, answer questions on a
particular subject on some network. Electronic networks have been used for
years to distribute information in this way. Some of the servers that are
available on local area networks have been:
File serving
Printers
Compute servers (such as supercomputers)
FAX
Mail services and archives
Bboard services
Modem pools
Shared databases
Text searching and automatic indexing
CD-ROM servers
Conferencing
Dictionary lookup
User's locations (finger)
Scanners/OCR
35mm Slide output
Wide area networks open up other possibilities for other services. Some
services will be offered because they are expensive to offer on a local
basis, because it requires some special expertise or machinery, or because
it is used infrequently on a local basis. Examples of wide area services
that could be offered: Current newspapers and periodicals Movie and TV
schedules with reviews Bulletin boards and chat lines Archive searching
through public databases Hobby specific information (ie sports scores or
newletters) Mail order shopping services Banking services Talk services,
bboard, and party line styles Directory information (both online sources
and Yellow Pages) Scientific papers Government databases, such as patents,
congressional record, and laws.
Library catalogs (eg. OCLC)
Weather predictions and maps
Usenet and Arpanet articles
Maps with driving directions included
Software distribution
Remote conferencing
Voice mail
Music and video archives
Pizza ordering
What services will be popular or commercially successful can only be
guessed.
C. Navigating through the "Directory of Services"
The Directory of Servers is an information server maintains a database of
available servers and how they are contacted. Like the white pages of the
phone system the directory should be easy and cheap to use and include
everyone. Equally important, this directory is easy to add to. Thus,
people with something interesting to offer are encouraged to add their
service to the directory.
A directory entry, however, should give enough information to understand
what the service is and how to connect to it. This entry is similar to a
yellow-pages entry in the phone book since the goal is to advertise the
service. A directory entry includes: (1) Description of server in English,
(2) the parent server if it is a subsidiary of a larger server, (3) related
servers, (4) public encryption key, and (5) contact information including
networks and contact points, (6) cost information. A local workstation
would keep extra information such as: (1) locally determined "score"
reflecting usefulness (2) subscription information (if any), (3) user
comments, and (4) time of last contact.
This information would be used to help determine when and if the server
should be contacted, and how the responses should be handled.
Navigating in the sea of servers to find new servers can be done using the
content navigation technique. In this way a question on classical music
would retrieve documents as well as directory entries. This could be done
by storing the directory entries on the local disk (in the cache) and
accessing it just like local documents based on the appropriateness of the
description. Thus retrieving the document would show all the directory
information. In that way, a user that is unaware of a certain server would
be presented with a description of that server with a listing of its hits
for the current question so that s/he could effectively evaluate its
potential value of the server. If the server is added to the list of
servers for that viewer, then it would be queried in the future.
Maintaining an up-to-date list of services in the cache naturally falls out
of content navigation and Dynamic Folders model because a directory of
services viewer would have the charter to keep itself up-to-date on
directory changes, and can be probed using content navigation. The
directory of services viewer would list the remote directory server or
servers in the sources slot. That way, the directory is kept locally and
is fast to access.
Cost and availability information can help guide the workstation to alert
its user to new choices of databases. If a new server appears in the
directory that is cheaper than the current server, then it could be
suggested as an alternative server. This can be complicated to do well,
but the benefits of not having the user cull through new directory listings
can warrant work in this direction. As Stewart Brand said, "One of the
problems with a market based system is that you are always shopping!"
Hopefully, the workstation can do some of the mindless part of comparing
servers.
Directories are classically owned and serviced by the communications
companies. In this role, the communications company is an unbiased party
that profits from the use of the system as a whole. Further,
communications companies generally take on a teaching role to get users
familiar with the system and aid those with problems. This has been true
with AT&T with the telephone, the different phone companies with the 900
numbers, and the Network Information Center for the Arpanet. Whether the
communications companies take over this role or not, the directory must be
supported by some organization or organizations that profit from the use of
the system.
D. Servers that Rate other Servers
With a large number of servers, it would be nice to know which ones are
sponsored by crooks, and which ones are gems. The directory of information
servers necessarily accepts all applications for inclusion, just as the
white pages do. Unlike the white pages, however, is a description (or
advertisement) of the server is included which can be misleading with the
result that users are charged for contacting fraudulent servers. Some
protection can be offered by independent servers that rate or grade other
servers. These servers can serve somewhat the same roles as Consumer
Reports, Better Business Bureau, and movie reviewers. This section
describes what rating services might do within the WAIS system.
Just as people use movie reviewers to help them select what movies to see,
rating services can help in the selection of quality servers. Servers that
provide "grades" or reviews of other servers will become useful as the
number of servers grow. These ratings can come in many forms such as a
numeric grade, formatted reviews that can be used with filters, or a free
form discussion. Thresholds can be used by different users to ensure that
a server is proven before it is used. This threshold might best be used in
conjunction with the cost so that even worthless, but free databases might
be tried.
These rating services can come from professional servers or from friends.
A user does not have to subscribe to just one rating service, since a
combination might be more useful. Combining information from multiple
ratings is an interesting topic for exploration. Creating the ratings
server with personal ratings could also be automated somewhat since, each
user's workstation keeps track of how frequently a server has been found
useful. This information, or any other, can be exported so that other
people can select servers that are commonly used.
Numeric ratings of servers can be merged into the user interface by helping
order the documents suggested to the user. Therefore, for some user,
articles from the Wall Street Journal might get better scores than a
similar article in the People's Enquirer. This information could also be
displayed by the color of the headline, for instance, so that unrated
services would not be overly penalized.
Just as movie goers start to trust a reviewer that has agrees with them on
past movies, users will trust rating services that they agree with.
Selecting a rating service based on this criteria can have some interesting
effects. The rating services that a user has agreed with the most will
single themselves out automatically. Users with similar tastes would then
find each other. With such an arrangement, one could be lead to find other
servers just because other users have liked it whether it is logically
related to the common servers or not. This is an automated form of the "if
you like this book, then you will like this other book" system. Further,
if two users like many of the same things, then they might want to meet.
A generation of server speculators can also arise. Since servers are paid
based on people using them, a ratings server will want people to use them
often. If agreeing with user's past evaluations is criteria for using a
ratings service, then predicting what people will like will be a lucrative
business. If a server turns out to be right, then it will be used more.
This type of speculation is closely related to the stock market advisers
that have become notable of late. A difference would be that this form of
speculation is trying to predict what will be interesting to people.
E. The Role of Editors
One of the conclusions from the NewsPeek personal newspaper project at MIT
(I hear) was that editors still had a place in the electronic age by
reviewing and selecting certain articles as important. Unlike the rating
services, an editor grades specific articles as whether they are important.
These grades are similar in many ways to the rating services and might be
able to be merged.
A Dynamic Folder might have a charter like: "any article from the front
page of the New York Times" which is a command to use what the editor
suggests the top articles are. Like the rating services, this can be
independent of the sources of the articles and combine the information from
multiple sources.
A form of editor server would be if users kept track of their favorite
articles and put them in a Dynamic Folder and exported it for others. This
way, many favorite servers might emerge and articles could be selected
based on friend's suggestions.
Automatically figuring out what the user thought of a document is tricky.
Clues as to what the user thought of it are: (1) how many folders point to
it, (2) if the user read it, how much of it, and for how long, (3) has the
user ever taken any information from it to be used in other documents, (4)
has the user ever referenced it.
This type of information could greatly improve users ability to deal with
the flood of available information. Furthermore, throwing away all the
thoughts a user has about a document is denying others of that mental
effort.
F. Markets and Hierarchies: Using Silicon Valley
Currently there are several online information providers and many online
information "brokers". Brokers provide the connections between the
workstations and the information providers (such as PC-link and
Compuserve). Sometimes these brokers have services of their own such as
electronic mail and bulletin board services. These brokers try provide a
complete information environment by providing access to servers. This
structure forces a new information server to be connected to many brokers
to have their product used since many users only use a few brokers.. The
airline reservation program Eaasy Sabre, for example, is available on 20 of
these broker networks. The approach of WAIS is to have an open system of
interconnection between users and servers where the brokers can act as a
server, but is not an all encompassing information environment. With an
open system we have a "market" of information servers rather than a
controlled environment or a "hierarchy"1 . Such a structure could open up
the field to many more servers and more sophisticated front-ends.
A market based approach would only standardize on the interchange formats
leaving different companies free to store and service queries in any way
deemed efficient. The user interfaces, similarly, are free to evolve to
fit users needs. Since the protocol is not "terminal oriented" (as most
systems are today), it frees the computers on either side to be
sophisticated in serving the user.
Rapid evolution of a technology can happen in a market system if the
structure is designed well. As long as the protocols are flexible enough
to start with, and a procedure for changing the protocol is established,
then the components will evolve independently by companies seeking to gain
a competitive edge.
Silicon valley is an example of a market based system that led to rapid
evolution of hardware in the 1970's and software in the 1980's. As the
needs of the customers became understood and defined, larger companies that
had good marketing and service reputations could make the profitable
components without the help of the plethora of small companies.
Information servers is an innately niche-based market given the diverse
information needs of the population. Furthermore, the industry is more
like a service industry than a manufacturing one because of the continual
need for updates and new information. For these reasons, the silicon
valley structure can help in the rapid evolution of this market.
The key is to have enough users to make the servers profitable. Since,
small companies can not wait long before investment turns to profit,
achieving early income is important to get the system started. A "critical
mass" of users might form if the first interfaces were inexpensive or free,
and a few useful servers were available.
G. How Server Companies Can Make Money
If the WAIS system is to take off, then server companies must be able to
make money. Companies that offer servers can make money by billing users
directly, using credit cards, or by using 900 numbers to have the phone
system bill the users. Direct billing is difficult to set up and can be
expensive to operate, but large providers might want to do this. Credit
card billing has been a popular one for information providers. This
enables any network to connect the user to the server and then the user is
charged for use of the server. Typically, the first transaction with a
server is a negotiation of how payment will occur and the allocation of a
password for future transactions. This could be automated in the WAIS
system so that the workstation could know how much the costs will be and
keep a total of everything spent. A risk with the credit card system is
that a credit card number in the hands of a crook can enable him to make
fraudulent charges. With the potentially large number of WAIS systems,
this might prove dangerous. Ratings services might be able to help weed
out the fraudulent information providers (if any).
Another approach is to use a phone company service over 900 numbers. When
a company is assigned one of these numbers, callers are charged per minute
of phone conversation and these charges appear on the phone bill every
month. Typically the phone company gets 50% of the revenue from this and
the charges range from $.10 to $2 per minute (PacBell gets $.25 for the
first minute and $.20 thereafter). This approach eliminates the need to
have a negotiation of credit card information and limits some of the risks
of disclosing a credit card number. On the other hand, the charge for
billing is high. Another limitation is that one must use the phone system
to connect with the server.
In any case, there is very low overhead in starting a server and earning
money. All one needs is a phone, a computer, and some desirable
information. This is crucial to the success of the system.
All methods of billing are likely to be used and should be supported by the
WAIS interfaces.
IV. The Protocol's Role in WAIS
"... they have all one language; and this is only the beginning of what
they will do; and nothing that they propose to do will now be impossible
for them"
Genesis 11:6
To connect a workstation to a server requires a communication network and a
language to talk. The communications network can be anything that allows
computers to communicate such as modems, Internet, or digital phone
networks. A protocol is the language used to relate questions and receive
answers between the workstations and servers. This section describes some
of the issues involved in this protocol.
A. Open Protocols Promotes Wider Acceptance
It is important to the success of this system to have an open protocol that
allows users to connect with servers. Several models for how to create an
open standard have been tried, such as: have a company own it and license
it (Adobe, for instance), have a university develop it (X Windows, for
instance), have a standards organization bless it (Common Lisp, for
instance), and simply make the specification available and declare is open
(IBM PC, for instance). Each approach has advantages and disadvantages.
The key point is that certain attributes be adhered to.
1. The companies that are developing the protocol must be open to using
existing standards, and not feeling that new protocols should be protected.
2. A system for enhancements to the standard should be set up. Standards
committees are often used for this.
3. The standard should be able to transmit data in a variety of formats.
There are many emerging multi-media standards. A good standard will be
able to transmit these information standards.
4. The query part of the protocol should be able to accept different
formats of queries. Queries might, eventually, have multimedia
expressions. These should be free to evolve with periodic standardization.
5. The query must have some method to transmit cost restrictions and
time-outs. It should also be able to handle query forwarding while
avoiding circularities.
An idea for a query language is to use English that is restricted by the
constructs that are understood by the servers. As systems become more
complicated, they can handle more English constructs. In this way, future
server systems can get more information from a query and produce more
appropriate responses, simpler systems might use the words in the query
without parsing the structure of the query. This approach would allow the
servers to change, while the not changing the human interface and the
protocols. The English language approach has been very successful for
untrained users of the Dow Jones DowQuest system.
The overall success of this system largely depends on how well these
protocols work and how they are made available. There is a standard that
could solve part of the problem: NISO Z39.50-1988. This standard can help
with connecting to servers, delivering queries, and getting responses back.
It does not specify the query language or the format of the retrieved
records. Other standards may be able to aid other communications needs.
B. Hardware Independence
Since this system depends on an open protocol rather than a particular
implementation, the workstation, servers, and communications systems can
all be made up of various hardware technologies that would evolve in time.
This independence fosters an appropriate use of all hardware pieces, and a
freedom to compete to produce the best components.
Each personal workstation platform has attributes that are appropriate to
exploit differently. These can be used to make tailored user interfaces.
Further, a competition for the best caching and selection criteria should
emerge which will hopefully settle into a good general standard. As
personal workstations start to handle audio and video, these can be
retrieved with the WAIS system if the bandwidth is available.
Nintendo, for instance, makes a home computer that connects to the
television that is installed about 25% of all American homes. They are
providing information services to 150,000 Japanese households using this
technology. This might be an attractive front-end to a WAIS system.
The server computers will range from personal workstations to
supercomputers. Most databases are under 1 gigabyte so they can be stored
and processed with a personal workstation unless there are a very large
number of users. Supercomputers will be used in applications where there
is a large amount of data or there are a very large number of users.
Supercomputers can offer superior query handling by doing extensive work on
each query.
The communications systems used should be any that are locally available.
The bandwidth requirements for text can be satisfied with current phone
systems using modems. As advances in bandwidth and connectivity emerge,
such as X.25, ISDN, and InterNet; then the range of offerings from the
information providers should go up.
Since no component is centralized, this system is free to be established
anywhere in the world. Other more centralized systems, such as Minitel,
have had difficulty in expanding outside of France. This system should
encourage independent regions to set up a compatible system because of the
availability of software for servers and workstations.
C. Protecting the User's Privacy
"Electrical information devices for universal, tyrannical womb-to-tomb
surveillance are causing a very serious dilemma between our claim to
privacy and the community's need to know."
Marshall McLuhan, Media is the Message
To encourage users to trust their personal machines with their data and
interests, we must be sure to protect people's sense of privacy. As
machines start to learn more about their users and start to contact other
machines on their user's behalf, the dangers to privacy are significant.
There are technical as well as legal issues involved. This section will
cover the technical issues in protecting privacy (any good ref for the
legal side?).
There is no easy way to protect a personal workstation if an intruder can
get at the keyboard. Since the workstation acts on behalf of the user the
potential damage that could be done by a crook at the controls would be
worse than is currently possible. Since users will be leaving their
computer on all the time so that it can contact servers and be used by
other servers, we lose the security of the computer being off at night.
One way around this might be to able to turn off input from the user while
leaving the computer on to contact servers over the network. If a user
knows that she is never around at night or on weekends, then this profile
might help lead the system to not trust off hour use and require a
password. The assumption so far in personal computers is that the machine
stays in a secure physical environment and all protection must be directed
to network connections. This is not a safe long term solution, and should
be thought through carefully.
Other risks are involved when dealing with networks. There are problems
with intruders, spies, and forgers. An intruder will try to read, modify,
or destroy data that the user did not intend to leave accessible. Spies
will watch the traffic from a user to determine the servers contacted and
the content of the messages. A forger will copy password information to
act like a different user.
Network intruders can be prevented from reading unwanted data by the user
only exporting certain Dynamic Folders to become servers for the outside
world. A question is whether we want "group" access as well as "world"
access as in the Unix file system or some other layered approach. A
Dynamic Folder only contains pointers to information. If the information
is on the local disk, should that be accessible by a remote machine?
Should those files be protected from being read? If the information came
from a remote database, should the requester be required to get it from the
source even if a copy is on site? What are the copyright issues here?
Spies can watch communications networks and collect passwords and credit
card data if this information is sent in clear text (not encrypted) as well
as read the data. A public key system makes sense in this application
because the directory information can include a key. Public key systems
are those that everyone can lock a message (encrypt) for a recipient, but
only the recipient can read it. Presumably the public key system would be
used in establishing a connection and a special key for the conversation
would be established. Current public key systems are too compute intensive
to be used for large volumes of data. A conversation key could be used
with DES or some other encryption system that is easier to compute (usrEZ
software has a product that runs at 30k characters/second on a MacII).
Adoption of such a system early in the WAIS development would ensure that
this type of protection is assumed in modern information systems.
Forgers can be foiled with a system of authentication. Authentication is
important when the charges are high or when the system is used for ordering
goods. One solution is to use a public key signature system that is easy
to implement using the public key system (ref the Public Key papers). A
signature is passed so that only the sender could have created it.
V. Conclusion: Why WAIS will Change the World
Historically, when the distribution of information became easier or less
expensive, and explosive growth in learning occurred. Wide area
information servers are a new way to distribute information. Since anyone
with a personal computer, a phone, and some information can be a server,
people are free to create and distribute their work in ways that paper
distribution made impractical. The current electronic databases, in
general, do not have a standard for interchange. Just as the railroads
were owned and controlled by relatively few people current database brokers
control access and hence the production of data. The highway system was
not owned by anyone and the incremental cost to start a new business was
very low. Small businesses flourished partly because of this. WAIS
systems, similarly, have very low initial costs and low distribution costs
which can pave the way to many servers in a short time.
Since the WAIS system is founded on computer to computer communications,
new servers that just learn from other servers and produce useful
information or analysis can become profitable. Such a server could be
thought of as "smart" and the better servers will learn from other servers
and from its own mistakes. Thus a distributed "smart" intelligence can be
formed.
BBoard systems have not produced any astounding works of literature, I
suggest, because it is difficult to reference older works. If older works
were easy to find and reference, then people would be more inclined to make
better entries. Better entries would get more references and be used more.
No BBoard systems, that I know of, make this easy. Since editors, content
searching, and archiving are all fundamental parts of the WAIS
architecture, we stand a better chance of high quality works being
produced.
A large server, or sage, has a role in this distributed system because it
can infer correspondences between many pieces of information. Further,
large servers will have many users that it can learn from. Users will
teach a server what is important just by using the server. Thus a large
server will be the place that great new ideas will be created based on lots
of existing information. This new form of intelligence, that is formed out
of many participating people and machines, is an exciting prospect.
VI. Related Documents
Blip Culture Hypermedia, Harry Chesley, Apple.
Catalyzing a Market of Wide Area Information Servers, Brewster Kahle.
Wide Area Information Server Demonstration, Brewster Kahle and Charlie
Bedard.
Electronic Markets and Electronic Hierarchies, Thomas Malone CACM June
1987.
Introduction to Modern Information Retrieval, Gerald Salton, Cornell.
McGraw Hill.
Parallel Free-text search on the Connection Machine, Stanfill and Kahle
CACM Dec 1986.
VII. Appendix: Comparisons to Existing Systems
There are always precedents to any system, this one included. Some are
academic and some are commercial; some are computer oriented and some are
human services; some are special purpose and some are generally useful.
A. Compuserve;(of Columbus Ohio, 1-800-848-8199) is a phone based service
with about 1000 services with 500,000 PC subscribers. It includes BBoards,
hobby services, home shopping, email, multiuser online games, etc.
Interestingly, they have contracted with the government to accept Export
License Application transactions and other user interface functions. They
have "Personal Newspaper" products and deliver data from many publishers.
They own a lot of the underlying communication system, but are afraid of
ATT and Baby Bells. They are building sophisticated user interfaces for
the PCs and MACs.
Compuserve is owned by H&R Block and charges by the minute. They handle
their own billing. They have recently bought most of their competitors
(The Source, Access, Software House of Cambridge, and Collier-Jackson of
Tampa Florida) and are making a fortune. They turned a profit in 4th
quarter fiscal 1985 and by the end of fiscal 1986 it recorded a profit of
$1.7 million on $100 million revenues and 300,000 users.
Compuserve is the closest model and can be easily accessed with the WAIS
system. On the other hand, WAIS helps you find the database you are
interested in, does not use a terminal interface (you use your PC with all
of its speed), and WAIS offers subscriptions to services where your PC will
keep itself informed automatically. Most importantly, WAIS is not "owned"
by anyone and is free to grow independently from a centralized company.
(For more technical information I have a book of their services, Thinking
Machines has an account, and I have a series of articles describing their
business activities.) B. Minitel; in France is an outgrowth of the phone
company. As an alternative to phone books, users were offered terminals
for their homes. Many people took the terminal. By all reports it has been
a very popular system. A 1986 news report said: "The directory for Minitel
services is now the size of a phone directory for a small city, evidence
that Minitel is a success." George Nahon, managing directory of
Intelmatique: "Then need to create a market of users emerged as a
prerequisite for a service." One reports speculated that France has put
about $500 million into the system by 1986.
Their interface is a terminal type interface and the servers are both human
and machine. [Europe is the most exciting continent for information
services. It seems that they take this very seriously, while the US
government has yet to take the bold steps of investment and
standardization.] C. NetLib; is a free Unix utility for distributing files
through the email. Anyone that has access to the servers via electronic
mail can make inquiries and file requests. This system currently has about
100 (a guess) collections world-wide and is growing. In 1987, about 10,000
requests per month were serviced. The bulk of the offerings are software
programs rather than raw data. Since no charges are made for queries or
requests this system is used by academics and researchers. ATT and Argonne
labs are supporting this work.
The automatic reply system (remote-machine-to-local-machine rather than
remote-machine-to-local-human interface) in NetLib is similar to the WAIS
system. WAIS, however, is not centered solely around EMail as a transport
layer; it uses the phone system as well for interactive use. Also, WAIS
would help find databases that are relevant and handle the queries and
requests through a more "user friendly" interface. (For more on NetLib see
Distribution of Mathematical Software via Electronic Mail in Communications
of the ACM May 1987) D. Switzerland system; Still assessing this system.
E. Lotus and NeXT text system Both Lotus and NeXT have text searching
systems that are similar to Thinking Machine's Dow Jones system, but are
based on local data (LAN based). Since disks hold close to 1 gigabyte
these days, and the entire CM at Dow Jones holds 1 gigabyte, we are close
in scope but not performance. On the other hand, a PC will serve its 20
users adequately and the new daily information can be effectively
distributed from Dow Jones and other places. Lotus seems to be getting
into the information distribution business and is writing software to
process that data locally.
These companies see themselves as critically involved in this area. I
believe cooperating with them is in our best interest.
F. Information Brokers Many companies act as brokers to other information
providers. Often these services will offer electronic mail and bulletin
boards. These private systems rarely communicate with each other. The
systems that I know of are listed below. If anyone has any information on
these or other companies, please tell me.
AppleLink(Personal Edition) 1-800-227-6364 getting info
Delphi 1-800-544-4005 getting info
Dialcom, Inc. 1-800-435-7342
GE Information Services 1-800-433-3683 getting info
This company services the fortune 500 companies with network and processing
services using Honeywell and IBM mainframes. They lease lines from ATT and
provide an environment for their customers including network services and
value added filtering and massaging of data.
GEnie 1-800-638-9636 getting info
IBM Information Network 1-800-IBM-2468 ext 100
INet 2000/TravelNet 1-800-267-8480 bad number
Inet 1-800-322-INET
NWI 1-800-624-5916
Quantum Computer Services since 1985, privately held, "multimillion
dollars" official commodore info service. Has been supported by commodore.
PC-link 1-800-458-8532 IBM PC product
Q-Link 1-800-392-8200 Commodore product
America online Mac product
Snet 1-800-272-SNET Dept AA
The Source 1-800-336-3366
StarText 1-817-390-7905
Travel+Plus 1-800-544-4005
US videotel 1-713-323-3000
Western Union EasyLink 1-800-779-1111 Dept 31
Minitel Services 1-914-694-6266
Omnet/SCIENCEnet 1-617-265-9230
Other systems that I would like to find out more about: Holland system,
Prodigy, Knight Ridder, Audio Tex, Airline Reservations system, Hospital
Ordering System, Verity, Personal Newspaper (Media lab), Information Lens
(Media Lab), SuperText.
G. Hypertext Hypertext and WAIS share many attributes for accessing textual
information. In some sense, WAIS is an attempt at a large-scale hypertext
system by allowing links to be deduced at run-time and across many
databases stored in many places. Since servers provide pointers to
documents, a pointer to a document can be put in a document and retrieved
at a later time. Thus document pointers can be thought of as a crude form
of hypertext link. This form of deducing hypertext links through content
navigation might lead to interesting paths that are tailored to a
particular user. Automatic systems will never replace the value of having
users suggesting links. Suggested links can be added directly to the
documents (as in most hypertext systems) or then can be made available in a
distributed manner through the favorites databases. In this way, users
that found certain articles to be similar or usefully viewed together can
put them in a folder and export it as a database. One might ask, "Does
anyone have these documents grouped in a server, and if so, what other
documents are in that server?" These databases could then be used by others
as evidence that they belong together. By combining many people's
groupings, one can navigate through large number of documents in
potentially interesting ways in a hypertext style.
1 Nelson, Ted. Literary Machines.
2 HyperCard by Apple (ref?)
1 Salton, Gerald. Introduction to Modern Information Retrieval, McGraw
Hill. 1989.
2 NeXT calls theirs the Digital Librarian, and Lotus calls theirs Megellan
(sp?).
1 Malone, Thomas, et al. Electronic Markets Electronic Hierarchies, CACM
June 1987 Volume 30, number 6.
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.