KERNEL32 Versions

The user-mode Windows kernel, KERNEL32.DLL, is the lowest-level DLL that is in all versions of both the Windows that runs on DOS and the Windows that used to be called Windows NT. For the former, now long extinct, KERNEL32 is the “Win32 Kernel core component” according to the file’s version resources. For Windows as we know it nowadays, KERNEL32 is the Windows NT BASE API Client DLL.

Version 4.0 is common to both Windows products. The Windows that runs on DOS never gets past 4 as its major version number. Client and server editions have different version numbers 5.1 and 5.2 before being reunited for version 6.0.

The version numbering gets arguably quirky for Windows 7, Windows 8 and Windows 8.1. These were each in their time promoted as a significant—even major—release, yet they all have the same major version number which anyway isn’t in any of the names. As if to acknowledge this as unsatisfactory, the major version number for Windows 10 actually is 10.

Builds

The following builds have been inspected for these notes. Most are from MSDN discs. Some, especially since Microsoft greatly reduced its shipment of operating systems on MSDN discs, are from service packs downloaded (typically as self-extracting executables) from a Microsoft website.

Builds are arranged in increasing order of the file version as recorded in the executable’s resources. This version number is readily visible using Windows Explorer either in a so-called infotip for the file or by accessing the Version tab in the Properties dialog for the file. Programmers know this version number as coming from the so-called root block of the version-information resource, specifically from the dwFileVersionMS and dwFileVersionLS members of a VS_FIXEDFILEINFO structure.

The date stamp shown for each version is more obscure. File dates are easily modified after the executable is built and are anyway liable to be shown differently when read from different time zones. However, there is in each executable’s header a date stamp which is set when the executable is built and which is not commonly changed afterwards. It is readily accessible to anyone with programming knowledge and appropriate tools, e.g., Microsoft’s own DUMPBIN utility.

The executables for Windows Vista SP1 and Windows Server 2008 are exactly identical.

64-Bit Windows

Microsoft’s distribution of early 64-bit Windows on MSDN discs is even less reliable than is my renewal of subscriptions. I seem never to have received a 64-bit edition of Windows XP. Since a subscription in 2007 produced no x64 build of the original Windows Vista, the copy inspected of that is from an OEM disc. The builds inspected for service packs are from self-extracting executables that have been downloaded from a free Microsoft website (which is, curiously, an order of magnitude faster than downloading disc images from the paid MSDN website).

Again, where two packages are shown for the same build, the executables are identical.

32-Bit Windows on 64-Bit Windows (wow64)

KERNEL32 is sufficiently low-level that its 32-bit executables for 64-bit Windows differ from those of the corresponding 32-bit Windows versions.

Again, where two packages are shown for the same build, the executables are identical.