From time to time, I am asked what the difference is between the various versions (or editions) of Windows 7. The concept of editions of the Windows operating system arose largely during the transition from Windows 95, Windows 98 and Windows Millenium edition which, broadly speaking, was a "windows, icons, menu and pointer" ("WIMP") interface with Microsoft DOS as the underlying operating system to Windows XP which was, comparatively, a monolithic operating system which integrated traditional operating system functions (such as file handling) with a WIMP interface.
Windows XP was launched with several different editions: Home, Home Premium and Professional. In a similar fashion, both Windows Vista and Windows 7 were launched with different editions. Comparing the editions of legacy versions of Windows, Windows XP and Windows Vista, is a bit pointless given that the question of feature comparison most likely relates to a current or prospective need to choose between the various editions of Windows 7.
Comparing Windows 7 Professional and Windows 7 Home Premium
According to Microsoft, the principal differences between the Home Premium and Professional editions of Windows 7 concern the user's ability, using the Professional edition, to
- run Windows XP programs in "Windows XP" compatibility mode using a piece of virtualisation software that may be downloaded separately, from http://www.microsoft.com/windows/virtual-pc/download.aspx;
- connect to company networks more easily and more securely using a technology called "Domain Join" and is therefore dependent upon whether the Windows 7 operating system is to be used in setting requiring interaction with network servers;
- perform backup and restore operations to a home or business network server.
Comparing Windows 7 Ultimate and Windows 7 Professional
Similarly, the principal differences between the Professional and Ultimate editions of Windows 7 concern the user's ability, using the Ultimate edition, to
- encrypt their file systems using a logical-disk encryption technology called "BitLocker"; and
- switch between any of 35 languages at runtime, a feature that is likely to be of benefit to anybody developing software for use internationally.
BitLocker ensures that the contents of the relevant logical disk may only be read using the installed operating system thereby preventing unauthorised access to data on a drive using an operating system capable of reading Windows NT File System ("NTFS") volumes but without necessarily observing the access control lists ("ACL") associated with individual files and directories. BitLocker can be used in conjunction with Microsoft Encrypted File System ("EFS") which provides for encryption of file systems while the operating system is running.