The Internet Archive discovers and captures web pages through many different web crawls.
At any given time several distinct crawls are running, some for months, and some every day or longer.
View the web archive through the Wayback Machine.
Web wide crawl with initial seedlist and crawler configuration from October 2010
TIMESTAMPS
The Wayback Machine - https://web.archive.org/web/20110107050356/http://www.searchengineoptimising.com/glossary/glossary-of-computer-and-internet-terms/twain
The actual meaning of TWAIN is somewhat unclear but it allows developers to make digital scanner and camera drives against a standard. Almost all scanners today adhere to this TWAIN standard.