Win7 (64-bit) system found that the data source ODBC is not configured with access data source connection & system, system32, syswow64 Overview

The local computer is a win7 64-bit operating system. When creating a database instance, you need to create an ODBC data source for the access database. However, after opening the ODBC data source, you can find that no access connection is configured in the addition, for example:

The following question box is displayed:

 

Solution: Open the "C: \ WINDOWS \ syswow64133" directory and double-click the "Export odbcad32.exe" file under the directory (this file was previously opened in the c: \ windows \ system32 directory ), after entering the ODBC data source management interface, the problem can be solved. So I traced the root to the operating system principle. Let's talk about system, system32, and syswow64.

 

Wow64 (Windows-on-Windows 64-bit) is a Windows operating system subsystem that can run 32-bit applications.

Program, and exists in all 64-bit versions of Windows.

Wow64 sub-system is a lightweight compatibility layer, which has the same interface in all versions of Windows. it is mainly used to create a 32-bit environment, so that 32-bit applications can run on 64-bit systems without any modification, it provides required interfaces.

Technically, wow64 is implemented by three dll: wow64.dll is the core interface of Windows NT kernel and is converted between 32-bit and 64-bit calls, including pointer and call stack control. wow64win. DLL provides a proper entry pointer for 32-bit applications. wow64cpu. DLL
Converts the processor between 32-bit and 64-bit modes.

If you look at the \ Windows folder in the 32-bit operating system, you will find two sub-directories: one named System and the other named system32. The system directory is Windows
3. x legacy, used to maintain Windows's downward compatibility with some old applications. Generally, 16-bit DLL files (and other supported files) are stored in the \ WINDOWS \ SYSTEM folder, 32-bit DLL files and different support files are stored in the \ windows \ system32 folder.

In 32-bit windows, it is very easy to maintain 16-bit and 32-bit DLL files, however, the 64-bit version of Windows does not support 64-bit and 32-bit DLL files.

In theory, Microsoft will create a folder named \ windows \ system64 to store 64-bit DLL files, but instead, microsoft has created a new folder named syswow64 to store 32-bit DLL files. At first glance, it seems that this folder should store 64-bit applications, but note that 32-bit applications should have stored their DLL files in the \ windows \ system32 folder.
The \ windows \ system32 folder still exists in 64-bit windows. However, Microsoft uses this folder as a 64-bit DLL repository, instead of a 32-bit DLL file. I do not know why Microsoft uses the \ windows \ system32 folder to store 64-bit DLL files, but it is understood that this is done for downward compatibility.