Service Pack
The leftmost digit, .x000, is the service pack release number (for example, 2.00.1239.2000 denotes Service Pack 2). By default service pack 2 will contain all of service pack 1. Microsoft documents all components of each service pack on their website http://support.microsoft.com
This convention has changed slightly with Windows Vista SP1. With Windows Vista the build string is shown as 6.0.6001.18063 with the last digit (x) of the 600x number representing the service pack (ex: 6001 = SP1, 6002 = SP2) and everything after as the exact build number.
Read more about this topic: Microsoft Version Numbering
Famous quotes containing the words service and/or pack:
“The summer soldier and the sunshine patriot will, in this crisis, shrink from the service of his country; but he that stands it NOW deserves the love and thanks of man and woman.”
—Thomas Paine (1737–1809)
“You’re nothing but a pack of cards!”
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)