OUT OF DATE - Historical Interest Only
W3 vs WAIS and Gopher
QuestionWhat's the difference betwen W3 and
WAIS? What's the difference between
W3 and Gopher? Why invent yet another
system? Which one should I use?
The data modelW3 is comparable to both WAIS and
Gopher , in that it is a client-server
information system running over the
internet. There is a difference
in the data models. The W3 model
is that everything (document, menu,
index etc) is represented to the
user as a hypertext (hypermedia)
object. There two navigation operations
are available to the user: to follow
a link or to send a query to a server.
Only certain documents are flagged
as having a search facility, and
not all documents have links, but
some documents have both. That's
a pretty simple model, and results
in a pretty simple user interface.
Two neat things fall out of this
model. One is that it turns out
that almost all other information
systems can be represented in terms
of W3 documents. A W3 user can interrogate
WAIS indexes ( example ) and Gopher
servers ( example ). This comes
from the flexibility of the W3 model
to describe other structures. A
WAIS database is a searchable document.
The hit-list returned by a WAIS server
(or any other query engine) is a
hypertext document with links to
the documents found. Gopher menus
(or any other hierarchical menu system,
including a file system) are represented
as lists of items linked to other
objects. The W3 system has an open
addressing scheme allowing links
to be made to any objects on W3,
WAIS, Gopher, FTP, NFS, or Network
Therefore, the Web is the SUPERSET
of the FTP, WAIS, Gopher and HTTP
This flexibility has allowed lots
of different kinds of data to be
put on-line by writing a simple script
to generate a hypertext "view" of
The hypertext model, then, is flexible.
It is also powerful as a communications
medium. To author a document in
hypertext is to communicate better.
It allows one to put in a link whenever
the reader might need background
WAIS lacks linksYou miss the links in WAIS in two
ways. One is when you are looking
for an index. You can't follow links
from an overview page to "browse"
through different indexes. You can
only use a master index (the directory
of sources) to find indexes. The
other way is that when you have retrieved
something, whether part of the FORTRAN
manual or part of a mail discussion,
you get it in isolation. You can't
follow links from that document to
Gopher menus lack textA Gopher menu is a dry list of items.
Each line has 80 characters in which
to describe an option. In practice,
to communicate with the reader, one
needs the full power of text formatting
in a number of styles. A plain list
turns out to be relatively infrequently
used when the author or the program
generating the document has a choice.
Note that the "Panda" project adds
some plain text to Gopher menus,
but this is only a small step toward
the flexible blending of links and
text which is hypertext.
Group workThe second big difference is that
W3 is designed to include collaborative
authoring (CSCW) so that groups
can share information, rather than
simply individuals disseminate it.
We only have a first stab at this
on the NeXT platform, as we were
overtaken by the web's success in
dissemination mode. XMosaic is bringing
this further along.
Deployment levelsThe W3 software was not (in May 92)
as deeply deployed as WAIS and Gopher
software. This is basically because
it takes more time to write a hypertext
client than a menu or query client.
(Also, because the initial W3 instigators
are paid to work for the world of
High-Energy Physics primarily). Updating
this in June 93, we see W3's own
"http" protocol move ahead of the
WAIS protocol in the NSF Backbone
packet count statistics. The number
of W3 servers is now similar to the
number of WAIS servers (around 100)
while smaller than the number of
Gopher servers (around 1000).
The W3 world is growing very fast.
Between May 91 and May 93, load
on CERN's W3 server doubled every
four months or less. There is widespread
recognition that hypertext is essential
for the next generation. It is planned
to merge the W3 and Gopher systems,
and there is no reason (apart from
server simplicity and, perhaps, response
time ... both strong issues in the
market) why both of these systems
could not use the WAIS protocol when
it settles down. However these distinctions
are largely practical details for
the web, which in using a number
of protocols, allows technology to
advance without anyone having to
suddenly change everything.
The ChoiceBear in mind:
So install W3 clients, and W3 servers.
If you want to install a Gopher or
WAIS server, fine: the W3 clients
will access it. If you install a
WAIS server, then you could install
the W3-WAIS gateway locally to save
- A W3 client can read data from any
- If you run a W3 server you can upgrade
certain parts of the documentation
to hypertext later.
- Hypertext is neat for representing
existing data easily. This you can
only try for yourself.