UPDATED: 10/22/09
A reader pointed out that there were significant and substantial changes made to the kernel as well.
Mark Russinovich talks about this in detail here:
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ORIGINAL POST: 4/15/2009
This has been gone over many times before but it came up recently so I thought I’d take a moment to write about it:
Why is Windows 7 listed as Version 6.1?
If you run “ver” from the command line you discover that Windows returns a version number of 6.1. Not 7.0.
This of course initiated the typical lame comments I hear like, “See – Windows 7 is just a service pack of Windows Vista! It’s just a dot-release and only fixes what was broken in Windows Vista.” (This is a direct quote from someone. You know who you are.)
Windows 7 is a MAJOR release
First of all, I really have to say something: You’d really have to be completely uneducated about Windows 7 to make the statement that Windows 7 is nothing more than a “big service pack” over Windows Vista. Windows 7’s technology & functional advancements are so massive, it should be obvious to anyone that’s kept up to speed with Windows 7 that it’s very deserving of a full version increment.
Yes, Windows 7 inherited the rich development foundation that Windows Vista provided.
Yes, Windows 7 inherited the overall user interface improvements that Windows Vista delivered.
Yes, Windows 7 inherited the superior security infrastructure that Windows Vista introduced.
Yes, Windows 7 inherited the diverse mobile solutions technologies that Windows Vista brought to laptops.
But Windows 7 also introduces:
- MANAGEMENT – Secure workstation lockdown from rogue applications through “Applocker”
- NETWORKING – Intelligent cache-accelerated file access over WAN connections using “BranchCache”
- MOBILITY – Seamless virtual access to corporate networking resources without a VPN thru “DirectAccess”
- SECURITY – Eliminate data leakage from mobile storage using “Bitlocker-to-Go”
- EASE OF USE – Enterprise Search accessible through the the desktop user interface.
- DEPLOYMENT – Desktop boot from single file distributables for flexible deployment using “VHD Boot”
- MANAGEMENT – Device-level configurable power management from the user interface
- COMPATIBILITY – Complete application compatibility through “Windows XP Mode”
- … and many other major functions that are written about online.
So what’s the deal with the “6.1”?
Two words: Application Compatibility. As it turns out, when applications install into Windows, many are frankly written poorly and only check the major version number. When they expect to see “6” and the operating system returns “7” to them, this can cause installation headaches when working with poorly written applications.
So to ensure that Windows 7 is as compatible as possible, we’ve made “Windows 7”, version 6.1 in the eyes of application installations so that the major version number does not change. To quote the blog:
“The only thing to read into the code versioning is that we are absolutely committed to making sure application compatibility is optimized for our customers.”
A thorough overview of this topic is available on the Windows Team Blog:
kurtsh
Kurt Shintaku's Blog 