Search engine indexing A-level Computer science (OCR) 1.3.4 (b)

What is a search engine?

• A search engine is a program that searches through a database of internet addresses looking for resources based on criteria set by the client.

Explain how search engine indexing works

• The order in which search engine resources are displayed is very important because it determines which websites users visit and use.

• Search engines rely on an index of web pages.

• Web crawlers are used to collect information about websites to build this index.

• Web crawlers work by traversing the Internet, web page by web page using links on websites.

• The web crawlers collect keywords and phrases from the linked web pages and add this information to the index.

• They also collect and add meta data from websites, which is the information specified by the website owner.

Discuss the challenges involved in maintaining an up to date search index.

• Crawling frequency: websites frequently change, keeping the index up to date requires frequent crawling. This can be resource intensive and may overload servers while infrequent crawling risks outdated information.

• Duplicate and Redundant Content: Search engines must detect and handle duplicate pages to avoid wasting storage and returning multiple identical results. Identifying duplicates efficiently is a challenge.

• Scalability: The web is vast and continuously growing. Maintaining an index that scales with this growth while providing fast search results requires significant computational and storage resources.

• Deleted or Moved Pages: Pages may be deleted or moved, leading to broken links or outdated entries in the index. Efficiently detecting and removing such pages is critical for index accuracy.

Discuss the role of metadata in search indexing.

Metadata in search indexing refers to additional information about a web page, such as keywords, descriptions, author, and page titles. This information helps search engines understand the content of the page and improve the accuracy of search results.

Role of Metadata:

1. Improves Relevance: Metadata such as keywords and descriptions helps search engines match pages to relevant queries, improving the accuracy of search results.

2. Enhances Search Ranking: Search engines use metadata (like title tags and meta descriptions) to help rank pages. Properly optimized metadata can improve a page’s visibility.

3. Facilitates Crawling: Metadata aids search engines in understanding the structure and purpose of the content, enabling more efficient indexing.

4. Rich Snippets: Metadata can be used for rich snippets, such as star ratings, prices, or event times, enhancing the visibility and attractiveness of search results.