The Discus system uses static HTML pages on your server to store its data. Thus, if one of these files becomes damaged or corrupted, unanticipated and undesired behavior can result when using the features of the program. Such corruption can be introduced through unintentional deletion of files, server crashes, or editing the files directly using an HTML editor such as Microsoft Front Page or Netscape Composer.

The Data Recovery utility assists in recovering from two types of page corruption: corruption of the top page, and corruption of pages within topics. Of course, the best way to recover lost data is to restore the damaged files from a recent backup. However, it is an unfortunate and frankly surprising fact that few people keep reliable backups of essential data.

The Data Recovery utility is not an "undelete" feature. Once a topic or subtopic is deleted using the administrative tools, it is gone. The Data Recovery utility is designed only to recover those pages which might have become damaged due to a server problem or undocumented editing.

Fixing a corrupted top page

Symptoms of a corrupted top page include:

• Having topics on the top page, but not being able to access them through administration
• In Netscape, the background color, text color, and link color of all utility screens (New Messages, Keyword Search, etc.) are black.
• The "Tree View" lists only the board title
• Utility screens (New Message, Keyword Search) do not list the topics on the board

There are two ways to recover the data from a corrupted top page: salvaging the page and regenerating the page.

Salvaging the page

Salvaging the page attempts to recover topic data from the top page, matching information from the page if it is not entirely lost. The salvage operation also attempts to recover your title message, top page settings, main message, and color scheme, minimizing the amount of work that you must do in the recovery. The salvage operation is also optimized for several corruption patterns that we have observed, including corruption introduced by Microsoft Front Page and Netscape Composer.

However, salvaging the page is not always possible. Regenerating the page (see below) will always work, so it is in your best interest to attempt to salvage the page before going for the full regeneration. If salvaging fails, you can simply do the regeneration and you will be no worse off.

To salvage the page, from the Data Recovery screen, make sure the "Salvage Page" option is checked, and click the "Run Data Recovery" button. When the salvage operation is complete you will be returned to the Board Manager. You should at this point go to the board and see if the topics page looks normal. You should also verify that the title message and main message are filled in through the Board Manager. Based on the success of the recovery, you may choose at this point to use the Board Manager to fill in the missing or incorrect sections (such as correcting the color scheme).

Regenerating the page

If the page salvage operation was unsuccessful for any reason, you can use the page regeneration function. This actually examines the directory structure of your board, adding each topic that is found to the top page. These topics will likely be out of order. In addition, the default color scheme, title message, and main message are all used, so these will need to be specified after restoring the page.

To run the regeneration function, from the Data Recovery screen, check the "Regenerate Page" option, and click the "Run Data Recovery" button. This will add all topics that are found to the topics page. You then may need to use the Board Manager to change the color scheme, change the title message or main message, or reorder the topics.

If the Data Recovery utility does not allow you to access the top page because it reports that the top page cannot be opened, you need to create a blank "board-topics.html" file in your "messages" directory prior to invoking this function. Set permissions on that file to 0777 (rwxrwxrwx) if you are on a unix server. Then access the Data Recovery utility and use the "Regenerate Page" option.

Fixing corrupted topic/subtopic pages

Symptoms of a corrupted topic/subtopic page include:

• Receiving an "Undefined Error Extracting File" error or an "Extract Error" when attempting to access administrative functionality
• Receiving a "File Not Found" or "Document Contains No Data" error when attempting to read the discussion through the user interface

To recover data from a corrupted topic/subtopic page, it is important to know in what topic on your board the corrupted page resides. Generally this will be apparent from the section of administration that you are attempting to access.

Access the Data Recovery utility, which will give you the form for recovering corrupted topic/subtopic pages. If you receive the form for recovering data from the top page (see above), then you first need to fix the top page. The "Automatically Fix Errors" box should be checked; if you want to see a list of errors that would be automatically fixed, uncheck this box. Click the "Run Data Recovery" button to run the data recovery process. A summary list of fixes that were made will be generated. If you unchecked the "Automatically Fix Errors" box, you must click the "Fix Errors" button to finish the Data Recovery procedure.

Data Recovery can only restore links to subtopics; it cannot restore the text of messages, about messages, announcement messages, or page structure. Thus, when a page has been recovered, use the Page Manager to customize the page and/or reorder the subtopics if necessary.