What are Cached Pages

Google takes a snapshot of each page it examines and caches (stores) that version as a back-up. The cached version is what Google uses to judge if a page is a good match for your query.

Practically every search result includes a Cached link. Clicking on that link takes you to the Google cached version of that web page, instead of the current version of the page. This is useful if the original page is unavailable because of:

Internet congestion

A down, overloaded, or just slow website

The owner's recently removing the page from the Web

Sometimes you can access the cached version from a site that otherwise require registration or a subscription.

Note: Since Google's servers are typically faster than many web servers, you can often access a page's cached version faster than the page itself.

If Google returns a link to a page that appears to have little to do with your query, or if you can't find the information you're seeking on the current version of the page, take a look at the cached version.

Let's search for pages on the Google help basic search operators.

Click on the Cached link to view Google's cached version of the page with the query terms highlighted. The cached version also indicates terms that appear only on links pointing to the page and not on the page itself.

Note: Internet Explorer users may view a page with any word(s) highlighted, not just search terms, by using the highlight feature of the Google Toolbar, which is mentioned in Part III.

When Google displays the cached page, a header at the top serves as a reminder that what you see isn't necessarily the most recent version of the page.

The Cached link will be omitted for sites whose owners have requested that Google remove the cached version or not cache their content, as well as any sites Google hasn't indexed.

If the original page contains more than 101 kilobytes of text, the cached version of the page will consist of the first 101 kbytes (120 kbytes for pdf files).

You can also retrieve Google's cached version of a page via the cache: search operator. For example, [ cache:www.pandemonia.com/flying/ ] will show Google's cached version of Flight Diary in which Hamish Reid documents what's involved in learning how to fly.

On the cached version of a page, Google will highlight terms in your query that appear after the cache: search operator. For example, in the snapshot of the page www.pandemonia.com/flying/, Google highlights the terms "fly" and "diary" in response to the query [ cache:www.pandemonia.com/flying/ fly diary ].

Use the Wayback Machine when you want to visit a version of a web page that is older than Google's cached version.

Exercises
These problems give you practice accessing Google's cached version of a page. For hints and answers to selected problems, see the Solutions page in the Appendix.

1. After Nelson Blachman received reprints of a paper he wrote for the June 2003 issue of The Mathematical Scientist, he wanted to discover what other sorts of papers appear in the same issue of this semiannual publication. Find a table of contents for The Mathematical Scientist for Nelson.

2. Compare the dates on the current page with the dates on the cached version for the following organizations:

CNN

New York Times

Linux Magazine

North Texas Food Bank

Note: Google indexes a page (adds it to its index and caches it) frequently if the page is popular (has a high PageRank) and if the page is updated regularly. The new cached version replaces any previous cached versions of the page.

3. Check the dates that the Wayback Machine archived versions of Google Guide.

This page was last modified on Monday January 02, 2006.


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