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:
“O good old man, how well in thee appears
The constant service of the antique world,
When service sweat for duty, not for meed!”
—William Shakespeare (1564–1616)
“You’re nothing but a pack of cards!”
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)