Note that many of the following links providing further information require a direct Internet connection to work.
For more information on any of the details in this document, please feel free to send mail to mosaic-x@ncsa.uiuc.edu (or, alternately, to the World Wide Web mailing list www-talk@info.cern.ch or the Usenet newsgroup comp.infosystems.www).
Mosaic
, and
the new class name for Mosaic is, predictably,
Mosaic
. Existing Mosaic 1.2 X resources and
application defaults files should be modified to match.
First, the multimedia X resources (e.g.
gifViewerCommand
) used by Mosaic 1.2 are totally
ignored by Mosaic 2.0. (Trust me, this is really a good
thing.)
Second, you now have complete control over the types of data Mosaic can understand and what it does with each type, as well as the file extensions that correspond to each type (when communicating with a HTTP0 or FTP server).
Third, Mosaic now uses the MIME typing mechanism for naming data
types (e.g., the MIME type for a GIF image is
image/gif
). This provides a substantial amount of
interoperability with the present and future of multimedia email
on the Internet, but will require a little readjustment on the
part of users who are used to simply calling GIF files "type
GIF", etc.
For more information on these issues, see:
This means that Mosaic 2.0 sends more complex queries to HTTP servers than Mosaic 1.2 did. If you are running a fairly recent HTTP0 server (e.g. NCSA httpd 0.5), this should not be a problem -- the new protocol is backward compatible, and Mosaic will go to great lengths to make sure it interacts with the HTTP0 server correctly.
However, some old HTTP servers (anything pre-1993) will break completely when sent a HTTP/1.0 query, and Mosaic 2.0 won't be able to make things work. Such servers are actually in violation of the final HTTP0 protocol specification and should at least be upgraded to conform to that specification, if not HTTP/1.0.
It is important to realize that HTTP/1.0 mandates server-side
typing of files. This means that the server must
recognize, for example, that the file extension
".gif
" means that the file is a GIF image (i.e.,
MIME type image/gif
), and must communicate this
information to the client within the HTTP/1.0 retrieval process.
HTTP/1.0 clients like Mosaic 2.0 will not look at file
extensions to determine file types when talking to HTTP/1.0
servers -- if the server gets the type wrong, the client will
not look at the suffix to try to figure out the right type.
This means that if all of a sudden a file that Mosaic 1.2 always handled as an HTML document is handled by Mosaic 2.0 as if it is a binary data file, and the file is being served off an HTTP/1.0 server, the server is (almost surely) at fault for not informing the client of the correct type.
Related issue: Transparent uncompression is currently
never done when talking to a HTTP/1.0 server. This will be fixed
in a maintenance release. We do however discourage reliance on
transparent uncompression in general, as clients on other
platforms (e.g. NCSA Mosaic for the Mac & Windows) generally
can't uncompress files compressed using the standard Unix methods
(compress
and gzip
).
(Note to the skeptical: server-side typing is actually a powerful feature of HTTP/1.0, despite any migration problems it may cause. Also note that Mosaic 2.0 will still do file extension typing when talking to HTTP0 servers, so you can always continue to run a HTTP0 server in conjunction with Mosaic 2.0 if you prefer client-side typing.)
Documents
and
Manuals
menus that were in Mosaic 1.2. They were
removed for a number of reasons too boring to go into here. If,
however, you find yourself "lost in cyberspace" because of the
loss of those hardcoded menus, choose the "Internet Starting
Points" entry in Mosaic 2.0's Navigate
menu --
Mosaic will fetch a document from NCSA that contains the contents
of Mosaic 1.2's hardcoded menus in HTML form.
Also see the new "Internet Resources Meta-Index", also under
Mosaic 2.0's Navigate
menu, for an alternate set of
Internet starting points perhaps more suitable to the task of
locating any specific piece of information on the network.
This provides a way to provide arbitrarily sophisticated front-end interfaces to databases and search engines, as well as other network services -- e.g., ordering pizzas.
See details on fill-out forms.
Currently, the "BASIC
" authentication scheme is
supported, which provides for encoded (not cleartext, but not
encrypted) transmission of password data across the network.
This provides a level of security at least as secure as, e.g.,
telnet
.
Once a user is authenticated on a particular server, Mosaic is smart about caching and reusing the authentication information in subsequent transactions with the same server in the same session -- the user will be informed at any time the cached authentication fails and will be provided with the opportunity to enter a new username and password again.
See the CERN authentication overview for more information.
For more information, see:
Note: since it is possible for Mosaic 2.0 to be compiled without native HDF/netCDF viewing support, your particular copy may not be able to view the above examples.
Among other things, this enables clean graphical distributed information space mapping -- a single image map can have hotspots corresponding to information resources scattered throughout various information servers across the Internet, and the user can jump to any of those resources with a single mouse click.
For an example of URL redirection in conjunction with image mapping, see the experimental Internet Resources Metamap.
Use the command line flag -ics
or the X resource
imageCacheSize
to set the size of the image cache in
kilobytes.
-dil
command line option or set the
delayImageLoads
X resource to True to enable delayed
image loading by default; it can be controlled on a per-window
basis from Mosaic's Options
menu.
See also the CERN HTTP/1.0 spec.
<BR>
(line break) and
<HR>
(horizontal rule) tags.
File->Refresh Current
provides a
convenient way to restore proper inlined image colors in a given
window if the colors have been previously stolen for another
window's inlined images -- keyboard accelerator (with pointer
inside the scrolled document viewing window) is
Capital-R
.
Documents
menu, for local site
configuration.
To take full advantage of Mosaic 2.0's capabilities, you should run a very smart HTTP/1.0 server. We recommend NCSA httpd. If you prefer a Perl-based server, try Plexus. Other options are CERN httpd and GN.
Experimental tutorials on various Mosaic-related topics are now available. Comments welcome (send 'em to marca@ncsa.uiuc.edu).