• 64 bit MDAC debuted with MDAC 2.7

• MDAC builds are compiled to 32 bit and 64 bit versions now

• 64 bit MDAC 2.7 is only available with Windows XP Client 64 bit (limited release)

• Windows .NET Server 64 bit will ship with 64 bit build of MDAC 2.7 sp1

• 64 bit MDAC is currently not available as standalone redist on web (MDAC_TYP.EXE)

•  There are NO TOOLS available to check the MDAC on 64 bit OS.

• If we suspect MDAC is corrupt, the only option left is to reinstall the LATEST SERVICE PACK for that OS.

MDAC Backwards Compatibility

• 32 bit MDAC components still exist on a machine in the SYSWOW

• There is no “thunking” between 64 bit and 32 bit. (COM+ apps excepted) To use 32 bit MDAC you must compile a 32 bit application

• 64 bit MDAC components live in “Windows\System32” and “Program Files\Common Files”

• 32 bit MDAC components live in “Windows\SysWow64” and “Program Files(x86)\Common Files”

MDAC 64 bit Components

• ADO

• RDS – (?)

• OLEDB

– Core Services

– SQL Server Provider

• ODBC

– Core (Driver Manager, Administrator)

– SQL Server Driver

• MSDASQL is NOT ported!

Apart from the above list there are NO OTHER DRIVERS / PROVIDERS available in the 64 bit environment from Microsoft.