NCSA Mosaic FAQ: Already Asked Questions

# Recent Questions with Answers

last updated August 5, 1993

Suggestion: You may want to use the Search... command under the File menu to quickly locate information in this document.

This document contains answers to questions regarding

- Problems using Mosaic
- Questions about Mosaic
- So, you think you've found a bug in Mosaic?

# Problems using Mosaic

### How do I download an image or sound to my machine, rather than viewing or hearing it?

There are two ways:

1. Setting the particular multimedia resource to dump causes Mosaic to prompt you for a local file save. See the documentation regarding Multimedia Resources.

2. In Binary Transfer Mode, under the Options menu, clicking the mouse button on a hyperlink causes Mosaic to prompt you for a local file save, regardless of the document's file type.

### Why don't WAIS URL's work?

Mosaic currently does not provide native WAIS support. To make up for this, we are now running a WWW/WAIS gateway at NCSA. Try using URL's of the form

    http://www.ncsa.uiuc.edu:8001/wais.server.name:port/blah-blah-blah

rather than

    wais://wais.server.name:port/blah-blah-blah

For example, the TMC directory of servers can be found at:

      http://www.ncsa.uiuc.edu:8001/quake.think.com:210/directory-of-servers?

We are currently adding native WAIS support to Mosaic; it should be available sometime this summer.

Please also note in the meantime that WAIS URL's probably won't even work if you have an environment variable like `WWW_wais_GATEWAY` set; sorry, this will all be fixed soon.

### I can't view PostScript documents located on a Gopher server!

That's right --- Gopher has its own typing system, which doesn't include a way to identify PostScript documents. Similarly, you can't view MPEG movies, listen to AIFF sound files, etc. through Gopher.

### Why can't I view .rgb images?

Mosaic may report an error if you access a link that points to an .rgb format image, meaning xv3.0 is not being used. Since xv3.0 is now available and can view .rgb files, all you need to do is download xv3.0 from export.lcs.mit.edu/contrib and compile it. (With Mosaic 1.1, your X resource `XMosaic*rgbViewerCommand` should be "xv" by default on non-SGI systems.)

### I can't view a file in format BLARGH via NCSA Mosaic!

See the answer to the previous question. If format BLARGH is one that Mosaic supports, set the appropriate X resource to point Mosaic at the appropriate viewer for that format. Otherwise, wait until later versions of NCSA Mosaic -- this will all be a lot more flexible and adaptable in the future.

(In the meantime, consider setting binary transfer mode to 'on' and transferring the file into your local directory to view with your external viewer.)

### How do I access an ftp site that is missing from Mosaic's list?

To enter an ftp site directly, select Open from the File menu and enter the URL in the text field, for example:

    ftp://siggraph.org/

### Why doesn't Search Keyword work?

Normally, the Search Keyword field will be greyed out, because most documents are not searchable indicies. If you are at a Gopher or WAIS search index, the Search Keyword will become solid, and you will then be able to enter a keyword into the text field to the right, when the mouse pointer is inside it. When you hit return in that text field, a search will be done, and the results displayed in the main document window.

To search the current document for a text string, choose Search... from the File menu.

If you are running Mosaic with Motif 1.2 or under HP/UX and are having problems with Search Keyword, more information is available here.

### Even though I'm on an SGI (or a Sun, or an HP), the Audio Annotate menubar entry is greyed out. Why?

Because you don't have `/usr/sbin/recordaiff` (for SGI) or `/usr/demo/SOUND/record` (for Sun) or `/usr/audio/bin/srecorder` (for HP) in place; more information is here.

### I can pull down group listings from my news servers but not any actual articles!

Your NNTP server apparently doesn't like to return articles named by message ID -- it will only return articles identified by group and article number. This is very bad, as the URL scheme Mosaic uses can only identify news articles by message ID. Your NNTP server is in violation of the NNTP spec (RFC 977) and should be investigated by your news administrator. (If your admin declares your NNTP server to be properly working, then feel free to send us a bug report, but we'll need read access to your NNTP server to do anything at that point.)

# Questions about Mosaic

### Is there a news group or mailing list discussing Mosaic?

Currently, comp.infosystems.www

### Where can I find Mosaic for a particular system?

The binaries are on NCSA's ftp server, ftp.ncsa.uiuc.edu, in the directory /Mosaic/xmosaic-binaries. Select the `.message` file for further information.

### What software (image viewers, sound players, etc.) do I need to support Mosaic?

See the documentation regarding Multimedia Resources.

### How do I edit hypertext, or, Is there an HTML text editor?

We may develop a WYSIWYG HTML editor at some point in the future, but for now, information on producing HTML documents is here.

If you use Emacs, try html-mode.el.

Information on converting LaTeX to HTML is here.

An RTF to HTML translator can be found at ftp.primate.wisc.edu in /pub/RTF.

### How do I set up a server?

The first-order solution is to simply place the documents you wish to serve on an anonymous ftp server and serve them that way. The corresponding URL would be

    file://machine.name/directory/filename

The advanced solution, to be used for performance and overhead reasons more than anything else, is to set up an HTTP server. There are several available; NCSA distributes a public-domain server, at ftp.ncsa.uiuc.edu in /Mosaic/ncsa_httpd In that directory are binaries, source code, and documentation on how to install and set up a server.

### How do I create the postage stamp images commonly used as hyperlinks to larger images?

The utility xv3.0, used for displaying images, also crops, expands, etc. You can download xv3.0 from export.lcs.mit.edu/contrib and compile it.

### Can a Mosaic hotlink run an external application?

No. This capability could prove to be a severe security hole. For example, a hyperlink may call a program which wreaks havoc on the reader's system.

### Can I put a hypertext link in an annotation?

Yes and no. Since the Annotate menu uses a normal, everyday Motif text widget for entering and editing annotations, there's no fancy hypertext editing capability -- yet.

However, if you understand HTML, you can freely use anchors in your annotation text (since NCSA Mosaic displays annotations as preformatted text, using the `<pre>` tag, which recognizes anchors).

### Why do you use a layer of indirection for audio annotations? Why not just have the annotation hyperlink point directly at the audio file?

Because then there'd be no way for you to subsequently delete the annotation, using the current scheme of things.

### Why has the default Postscript viewer been changed from Ghostview to dump?

Resource `postscriptViewerCommand` is now "dump" by default. This is because ghostview-1.4.1 and earlier ran ghostscript in unsafe mode and a malicious PostScript file could have caused damage to your filesystem as a result.

The current release, Ghostview-1.5 is available from ftp.cs.wisc.edu in /pub/ghost/ as 'ghostview-1.5.tar.gz', and invokes ghostscript with the -dSAFER command-line option by default.

# So, you think you've found a bug in Mosaic?

### Mosaic has trouble finding local URL's after accessing ftp URL's:

The process of going from partial URL to full URL depends very much on the current context, which is not easy to track such that the user is never surprised. After we move to libwww2, (Mosaic 2.0) we'll try to fix the problem.

Version 1.2 now recognizes URLs with 'localhost' as machine name to resolve this problem:

    file://localhost/path/filename

### Mosaic crashes after recovering from a data transfer with Control-C:

This is a problem on the Sun version, mostly, which will be fixed in version 2.0, once interruptable I/O is in place.

### After installing the CERN HTTP daemon, inlined images do not appear:

The CERN HTTP daemon containues to corrupt images and other forms of binary data. The easiest thing to do is to use the NCSA HTTP daemon instead (ftp.ncsa.uiuc.edu in /Mosaic/ncsa_httpd; binaries and source are available), as it will always pass through data unchanged and your images will show up correctly.