# Extending the Web

The World Wide Web is deliberately extensible. You can easily add new document formats to the Web just by documenting them and providing viewers. There are two major document type extentions in use today:

- Where the structure or content of the document is paramount, use SGML (Standard Generalized Markup Language, ISO 8879). A free viewer called Panorama is available from SoftQuad Inc. For other products see The SGML/Open Consortium.
- Where the presentation and graphical appearance of the document is paramount, one format to consider is Adobe's Portable Document Format.

# Acrobat and the Portable Document Format (PDF)

Acrobat(tm) is the name of a family of software from Adobe Systems, Inc. Acrobat software deals with files in the Portable Document Format, or PDF. If you think of PostScript as both a programming language and a marking language, think of PDF as just the marking language, with all the programming "expanded" or "unrolled". PDF is good for exchanging documents where you want it to look pretty regardless of whether the recipient has a Mac, MS-Windows, UNIX/X Windows, or even MS-DOS.

PDF also includes several hypertext capabilities, including "bookmarks" and "hyperlinks". The textbooks in this directory demonstrate both of these capabilities...

# How can I view PDF files?

You need to:

1. Get and Install a viewer.
2. Tell your Web viewer about the PDF filetype and the PDF viewer.

## Installing a Viewer

If you are on SunOS or Solaris, you can use Adobe's free AcroRead program. We have a copy of it on the CD, for you to install. Or, you may wish to FTP the latest version.

If you are on Linux, you can either ftp the latest Ghostscript.

As an alternative under Linux, or on other UNIX platformst that support MS-DOS or MS-Windows emulation, you can install the DOS or MS-Windows version of Acrobat Reader for use under dosemu, Wine, Wabi or whatever. This has not been tested!

On platforms other than those listed, you may wish to contact Adobe's Web Site to see if there is software for your platform.

## Telling your Web Viewer about PDF

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