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  Session Time-Outs

About Session Time-Outs

Session Timeout Alert

The Library of Congress Online Catalog is currently set to timeout after 5 minutes of inactivity. Timeouts are necessary due to simultaneous user limits that must be in place in order to assure an acceptable level of system performance. A "Session Timeout Alert" service is now in place that provides the user with a continuous count down clock displayed in the lower left-hand corner of the browser window in the status bar, as well as a pop-up window alert that appears 1 minute prior to timeout. From the pop-up box, users can easily refresh the session and restart the 5 minute clock. In addition, if a timeout does occur, the user will have the option of restarting their session and returning immediately to the most recent search conducted.

Special Note to Users of Screen Readers: The current implementation of this feature is not currently recognized by screen readers like "Window-Eyes." The Library is aware of this problem and is exploring various solutions.

Special Instructions for Firefox Users: In order to get the full benefit of this new timeout warning feature, you will need to enable the browser's status bar, which is generally disabled by default. To enable this feature, start Firefox, select Tools, then Options and a pop-up window will appear:

Image: Firefox Settings

Make sure that the "Globe" icon (Content) is selected (shown above), then select the "Advanced" button (found to the right of the "Enable Javascipt" line). In the resulting window, select the box next to "Change status bar text" (a check mark should appear as shown below).

Image: Status Bar Text

Select OK twice in order to close both windows and save the update.

Special instructions for Opera Users: In order to get the full benefit of this new timeout warning feature, you will need to enable the browser's status bar, which is generally off by default. To do this, start Opera, select Tools, then Appearance, and a pop-up window will appear:

Image: Opera browser appearance screen

From this window, select the Toolbars tab, enter a check in the Status Bar box, and select OK to accept the change.

Image: Opera Toolbars Screen

Why Are Time-Outs Necessary?

In order to assure the that the Library of Congress Online Catalog is available to all, a limited number of session ports must be shared by all public users. In order to assure that ports are always available, sessions which are inactive for more than 5 minutes are automatically disconnected. (see information on the Time-Out Alert above)

After 5 minutes of inactivity, users who try a catalog action will receive a message that their Session Has Timed Out and that they must "Start Over."

Time-out Errors and How to Fix Them

If a browser prohibits the reloading (and refreshing) of a Web page, it is unable to update the session ID and will return an error.

When a session times out (and the browser is set to "never reload") and "restart" is selected, the Online Catalog will attempt to reload the earlier session. Since the ID attached to that session indicates the session has timed out, the user always gets back the message that this session has timed out, and no new search can be initiated!

Some users find that their attempts to restart a catalog session result in a "timed-out" error message. This happens when a user's Internet browser preferences have been set to prohibit the reloading (and refreshing) of Web pages that have been previously visited and stored in its cache.

The Solution:

Fortunately, it is easy to fix this problem! Users must change the default settings on the browser to allow new versions of web pages to be loaded. The process is slightly different for Internet Explorer and Netscape.

IMPORTANT: Because there are many versions of each browser in use, the exact location and the text of each menu choice in your browser may be different from those in these instructions.

Firefox Users:

First, in the address box at the top of your browser type in the words "about:config" just as written here, with no spacing or capitalization (and no quotation marks either!)

Next, you will now see a long list of preference names in alphabetical order--the names are all strings of several words separated by dots, but may vary slightly depending on your Firefox version.

Scroll down until you find the line for "browser.cache.check_doc_frequency" and take a look at the settings to the right of that name; they probably say: default, integer, 3. If it says something else, you or someone else has already modified this setting in the past.

Next, we go to a page on the Mozilla site to understand what the default settings mean. (If you want to go there yourself, open a second browser window so you don't lose your place in the about:config). At http://www.mozilla.org/quality/networking/docs/netprefs.html we find the list of values for browser.cache.check_doc_frequency, given as:

1 = Every time I view the page
0 = Once per session
3 = When the page is out of date (default)
2 = Never

So, you may wish to change your setting to 1 so that all pages reload every time you use them. This will slow down your overall performance, but certainly avoid any timeout errors.

To change the setting, go back to the about:config list and right-click on the "3" (or click and hold on a Macintosh) until a menu comes up. Select "Modify" from the menu, and type your new value, 1, into the box and click "Ok."

From there, you can resume your browser use as usual. You may want to keep a record of this modification, in case you decide to change it back later.

Internet Explorer Users (assumes version 5.x):

The setting is called "Check for newer versions of stored pages."

  1. Starting in the Tools menu at the top of the screen, select:
  2. Tools > Internet Options > Temporary Internet Files - Settings
  3. Under "Check for newer versions of stored pages", select:
    Automatically.

Netscape Users (assumes version 4.5/4.7):

The setting is called "Document in cache is compared to document on network."

  1. Starting in the Edit menu at the top of the screen, select:
    Edit > Preferences > Advanced > Cache
  2. Under "Document in cache is compared to document on network", select: Every time.

IF THE PROBLEM PERSISTS...

If the above steps do not clear up the problem, you can usually force a server reload of the search page by holding down the [Shift] key while clicking Reload in Netscape, or by pressing [CTRL][F5] in MS Internet Explorer.

Use the browser's [Back] button to resume searching.

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June 25, 2008