There are so many threads being created asking the same things over and over again, so I figured that a FAQ could be useful...
If anyone has suggestions for more things to add, let me know. 1. When is Windows 7 being released?
Windows 7 was RTM'ed (R
anufacturing; this means that the code is final, and all the teams have signed off on it) on 2009/07/22
. The first people to get the official build will be the "royalty OEMs" (the big manufacturers, like Dell, HP, or Sony), on 2009/07/24
. After that, MSDN and TechNet subscribers will get it on 2009/08/06
. Windows 7 will continue to dribble out to various special groups like Microsoft partners and volume licensing customers (governments, corporations, or other large organizations). General availability, which would include Windows bundled on PCs, retail copies, preorders, and OEM copies that you buy from Newegg will be 2009/10/22
. 2. What is the final RTM build number?
Windows version numbers take the form of major.minor.build.QFE. According to a Microsoft employee
, the final build is 6.1.7600.16385
, built on 2009/07/13 at 12:55 PDT. When RTM makes its way to MSDN/TechNet, this can be verified. 3. What are the SHA-1 hashes for RTM, and how do I check them?
According to MSDN, the final RTM SHA-1 hashes and filenames for Windows 7 English are (in sha1sum format):
; Windows 7 Home Premium (x86) - DVD (English)
; Windows 7 Home Premium (x64) - DVD (English)
; Windows 7 Professional (x86) - DVD (English)
; Windows 7 Professional (x64) - DVD (English)
; Windows 7 Ultimate (x86) - DVD (English)
; Windows 7 Ultimate (x64) - DVD (English)
As for checking hashes, Windows users can use HashCheck
, which is free and open-source, and for Mac/Linux users, the sha1sum
command line utility is a standard part of the system. 4. What is RTM, GA, Retail, and OEM?
RTM is when the code is completed and signed off. GA, or general availability, is when that RTM'ed code is finally made available to the general public. Even though there is a full three months
between RTM and GA, there is no difference between the RTM code and what you get when you get Windows at GA. The RTM bits are the GA bits. RTM is "we're done with the code", and GA is "we're done with the packaging, distribution, marketing, etc., and are read to sell it".
When GA comes, you can get Windows in two flavors: retail, which is what you buy at a store, is a less restrictive license (you can transfer it between machines, as long as only one machine is activated at a time), and you are entitled to support from Microsoft. OEM is a cheaper license, that you get when you get Windows bundled with a PC or if you buy a "system builder" copy from places like Newegg. OEM is cheaper because it's locked to a system (you can't transfer your license to another machine), and you are not entitled to tech support (the person who built your computer is responsible).
Generally speaking, there are two types of OEMs: regular and "royalty". Regular OEM is what you get when you buy a "system builder" OEM Windows. Except for the label on the disc, regular OEM discs are the same as retail discs, and they install the exact same bits as a retail disc. The difference is not in the disc, but in the key: if you activate Windows with a OEM key, that key is forever tied to your system, whereas if you use a retail key to activate, you can move that activation to another computer in the future.
The big PC makers like Dell, HP, and Sony are classified as "royalty OEMs" by Microsoft. They will often customize their disc by including logos, extra drivers, and/or hotfixes. Their discs will also include a special certificate that Windows uses to authenticate your computer's BIOS (which lets the royalty OEMs use something called SLP, which sorta allows them to bypass the hassle of activation). 5. What if Microsoft finds bugs between RTM and GA?
Any bug fixes made after RTM will be released in the form of a hotfix that you can get through Windows update. Since there is a lot of time between RTM and GA, it is likely that when you install Windows 7 on October 22, you will be greeted by a long list of updates to install from Windows Update. 6. Why "7600"?
The Windows client (consumer) folks like to play games with build numbers. Windows 98 was build 1998, Windows XP was build 2600
(which Microsoft specifically targeted as a nod to the hacker community), and Vista was 6000. The non-consumer Windows folks are less keen on number games. Every NT up to and including Windows 2000 was just the build number that they happened to be at, and Windows 2003 was 3790; after 2003, the client and server groups synced up, and now all the build numbers are cute and round. Also, starting with Windows Vista, the lower 4 bits of the build number is now reserved for the service pack (according to a rumor that a Microsoft employee subsequently confirmed over at another forum), which means that the final build number must have the lower 4 bits clear--put in other words, the final build number must be a multiple of 16. And since they also want the number to look pretty (multiple of 100), this meant that the final build number had to be a multiple of 400 (LCM of 16 and 100). Rumor has it that Microsoft originally wanted 7200 to be RTM, but they overshot it, so now we have 7600 as RTM. The multiple-of-16 is why it's not
going to be 7700 or 7777 or anything like that. 7. How can I (legally) activate Windows 7?
If you are using a pre-RTM build, the latest (leaked) version that supports the freely-available Beta and RC product keys is build 7260. Builds after that cannot be activated without using an illegal hack.
If you are using a RTM build, you cannot activate Windows before GA unless you are "special" and can get an early product key (e.g., if you are subscribed to MSDN/TechNet or are a Microsoft partner). For everyone else, you have to wait for GA. Some people have suggested using the "rearm" mechanism (running "slmgr.vbs -rearm" from an elevated command prompt
) to extend your activation grace period from 30 days up to 120 days (which should be enough to cover the three months between RTM and GA). Although this is technically
an abuse of Microsoft's rearm mechanism (since it was intended for use by OEMs to return the system to a clean slate for imaging purposes), Microsoft has never made any indication that it cares about the use of this built-in function in Windows. 8. How do I get the x86-64 version of Windows 7?
The retail Home Premium, Professional, and Ultimate versions of Windows will come with both the x86-32 and x86-64 discs (it is not clear if it will be one dual-layer disc with both or two separate discs, though it is probably two separate discs). When buying an OEM "system builder" version, you will have to specify which edition you buy. When getting Windows preinstalled on a system, you will have to specify which version you want (if the manufacturer lets you choose). 9. What are the advantages and disadvantages of the x86-64 version? The good:
* Support for more than 3 GB of RAM (with proper motherboard support; some older chipsets, like the Intel 945GM, do not allow the addressing of all 4 GB, even if your OS supports addressing all 4GB)
* Potentially faster execution resulting from the ability to operate on larger chunks of data and the addition of new registers (x86-32 being a register-starved architecture, this helps). This speed up requires that the program be compiled natively for x86-64, and the actual gain will vary from program to program.
* Future-proof. 32-bit will eventually die out one day. Could be many, many years down the road, though.
* Slightly more secure than the 32-bit version. The bad:
* x86-64 requires more memory (and disk space) because the code is inherently larger, and because Windows has to also load the Wow64 libraries into memory (the stuff needed for backwards compat with 32-bit programs) (and keeping an extra set of DLLs around for 32-bit programs will eat up more disk space).
* All drivers must be signed. This is good (for security) but also bad (for small custom software that can't afford driver signing). The ugly:
* You have to make sure that you have 64-bit drivers. Some manufacturers, such as Dell, haven't released 64-bit drivers for some of their older hardware.
* 32-bit shell extensions won't work.
* 16-bit programs don't work (not really a limitation of Windows, but of how AMD designed x86-64). 10. What is the cheapest way to buy Windows 7?
Microsoft is offering time-limited half-price preorders of Windows 7, for shipment when GA rolls around on October 22. This half-price offer has expired in the US, but may still be active in other regions. As a point of reference, under this deal, a Home Premium upgrade was $50 USD, and a Professional upgrade was $100 USD. If you missed out on this deal, Microsoft has confirmed that it is offering a "Family Pack" for Home Premium in "select markets", which consists of 3 Home Premium upgrades for $150 USD (the same per-license price as the time-limited half-price preorder special). 11. Will I need to do a clean install when upgrading?
In-place upgrades (upgrades that do not require a clean install) are possible only if you are upgrading from Vista, and only if you are moving to the same or a higher edition (e.g., you can do an in-place upgrade from Vista Home Premium to Windows 7 Home Premium or to Windows 7 Ultimate, but not from Vista Ultimate to Windows 7 Home Premium). In-place upgrades also require that you have the same "bitness"; i.e., upgrading from 32-bit Vista to 32-bit Windows 7 is supported, but not 32-bit Vista to 64-bit Windows 7 or 64-bit Vista to 32-bit Windows 7. Finally, European users who have the "E" edition cannot perform an in-place upgrade. For all of the unsupported scenarios, such as upgrading from Windows 2000, Windows XP, Windows 7 Beta/RC, or upgrades that result in an "edition downgrade" (e.g., Vista Business to Windows 7 Home Premium), you must do a clean install. Note that these restrictions only apply to in-place upgrades. An upgrade license will allow you to go from Vista Ultimate to Windows 7 Home Premium or even from Windows 2000 to Windows 7 Ultimate x64; it's just that you won't be able to do an in-place upgrade and must instead do a "clean install".
Note that, even if an in-place upgrade is supported, it is generally recommended that people perform a clean install anyway. 12. Do I have to back up my data for a clean install?
It's always a good idea to back up your data for a clean install, but you don't have to
unless you are also formatting the hard drive. By default, a clean install simply renames the old "Windows" directory to "Windows.old", and all your old files are preserved--they just now exist under different directory names. If you tell the installer to format the hard drive, then, yes, you will need to back up any data that you do not want to lose. 13. Why doesn't the Windows 7 disk ask me which edition I want to install?
The Vista installers asks for the product key before
it installs Windows, and it uses the product key to determine which edition to install. If no product key was given, it will ask the user to select an edition.
This is not possible for Windows 7, because the product key input has been moved to after
the install, which means that the installer cannot determine the edition from the product key. Asking the end-user which edition to install is very confusing (remember, in Vista, the user is asked only if no key was given), so Windows 7 has returned to the old XP style of using different discs for different editions, and an Ultimate disc can only install Ultimate.
However, the install.wim should still be the same and should still contain all editions (this is necessary to support Windows Anytime Upgrades), so if you simply delete "ei.cfg" from your ISO, you can force the installer to ask you which edition to install (you will still need the appropriate key for each edition, of course).