Language English

Launched September 2, 1993
Closed November 8, 1996

Developer Oscar Nierstrasz

Country of Origin Switzerland

1993 - 1996 Oscar Nierstrasz

Topic Universal

Region No Limitation

Technical functionalities
Manually by an editorial team selected sites search engine

Used SeEn W3 Catalog

Older Version Internet Archive / WebCite

Mauro Orlandini (1993): »A new experimental catalog of World Wide Web resources is now available, courtesy Dr. O.M. Nierstrasz, Centre Universitaire d'Informatique in Geneva.« Source

Oscar Nierstrasz (1993): »An experimental catalog of WWW resources is now available at: It uses a simple, generic search engine package written for Plexus (called `parscan') that searches a file of HTML paragraphs. If you run Plexus, you may find it useful for implementing other catalogs.« Source

Wikipedia: »W3 Catalog was a very early web search engine, first released on September 2, 1993[1] by developer Oscar Nierstrasz at the University of Geneva. Unlike later search engines, like Aliweb, which attempt to index the web by crawling over the accessible content of web sites, W3 Catalog exploited the fact that many high-quality, manually maintained lists of web resources were already available. W3 Catalog simply mirrored these pages, reformatted the contents into individual entries, and provided a Perl-based front-end to enable dynamic querying. At the time, CGI did not yet exist, so W3 Catalog was implemented as an extension to Tony Sander's Plexus web server, implemented in Perl.« Source

Kate Johanns (2017): »..., the W3 Catalog was one of the first attempts to create a searchable catalog of web resources. Professors at the University of Geneva, inspired by a Tim Berners Lee seminar on the World Wide Web, set out to index internet resources. It was easy to envision the potential of the online world; navigating it was another matter. Professor Oscar Nierstrasz wrote a program that downloaded human-curated website directories and compiled them into the W3 Catalog. Although the W3 Catalog was designed to be self-sustainable, in truth it was tedious to maintain, Nierstrasz admitted on the W3 Catalog history page. Someone had to track and ensure links to directory websites continued to work. Plus, the popularity of the W3 Catalog sometimes overloaded the server on which it was housed.« Source

»Searches nine large, frequently updated lists, including:
NCSA What's new
CERN's W3 Virtual Library Subject Catalog
Martijn Koster's Aliweb Archie-like Indexing for the Web
Scott Yanoff's Internet Services List
Run by Centre Universitaire d'Informatique, University of Geneva
A multi-threaded search
Generates queries to many search engines
Presents results as one document
User-selectable searching time« Source


Oscar Nierstrasz (1996): »The search engine (briefly called ``jughead'', but soon renamed ``w3catalog'')...« Source

Critical points

Features & Functionality

Oscar Nierstrasz (1996): »At the time, the CERN http server seemed to be very difficult to configure to run ``active pages'' (i.e., pages whose output would be dynamically generated). The search for a better platform led us to switch on August 10, 1993 to the Plexus server, implemented in Perl. This made it very easy for us to install ad hoc search engines for The Language List and the OO Bibliography Database as Perl packages directly integrated into our server. Since the ability to set up a search engine seemed generally useful, I decided to implement a simple, configurable Perl package for the Plexus server that could easily be adapted to different applications. (Basically, all the package - called - would do is return all the HTML paragraphs matching an ISINDEX HTML query string.) Parscan was made available September 2, 1993. At the same time, I noticed that many industrious souls had gone about creating high-quality lists of WWW resources, and made these lists available as part of other services, such as CERN's WWW Virtual Library. The only problem with these lists is that they were not searchable. With parscan, a simple solution suggested itself: Periodically download lists of resources using a Perl script that connects to the HTTP servers where the lists are stored (such mirroring programs are now common). Use an ad hoc Perl script to reformat the lists into individual HTML paragraphs (or ``chunks''), and glue all the chunks together into one searchable file. Provide a parscan interface to query the file.« Source


References & further Publications

Wikipedia (EN):
Wikipedia (Others): n.a.

Other Sources

Mauro Orlandini (1993-96): The What's New TeSRE Archive URL:
Oscar Nierstrasz (1993): Searchable Catalog of WWW Resources (experimental) URL:!topic/comp.infosystems.www/IXZSajbci9M
Oscar Nierstrasz (1996): W3 Catalog History URL:
Kate Johanns (2017): Tech Time Warp: W3 Catalog Makes the Internet Searchable URL:

Created: 2018-02-24