Purpose of Qchain in hotfixes?

[pmcx9]

A learned friend gave me a copy of his hotfix batch file and it has this reference after all the hotfixes have been applied in it.

I obviously have qchain.exe in my hotfixes directory.

Is it necessary?

ECHO.

ECHO Running Qchain

start /wait %systemdrive%\install\Hotfixes\qchain.exe

ECHO.

[GreenMachine]

Windows XP was supposed to have QCHAIN functionality built into the hotfixes, but it turns out that some of the earlier patches do, in fact, still need it. The exact date is somewhere on MS's site.

For info: Hotfixes create a list of system files to replace on the next boot. This list is created in the order the hotfixes are run. If run out of order, an older file version may overwrite a newer one. QCHAIN sorts the list of files to be replaced, putting the files in a oldest to newest order to prevent this problem.

I used this method before integrating the hotfixes into the install, and even if run when not needed, it will not harm the instalation / fixes.

[pmcx9]

thx for fast reply

could this be the answer to the mdac not always installing or has that already been solved?

[Aaron]

MDAC has a funny way of installing and its not the same as the other regular hotfixes. It doesn't have anything to do with QCHAIN though, because none of the current hotfixes have the same files as MDAC has (AFAIK).

Here's a particular command I use to install MDAC, this should help you:

start /wait %systemdrive%\install\hotfixes\Q823718.exe /T:%systemdrive%\install\tmp /C:"%systemdrive%\install\tmp\dahotfix.exe /q /n" /Q

You do not have to create the install\tmp directory, its created automatically and is a place for the hotfix to extract to before installing.

[pmcx9]

The reason I propmted the qchain theory regarding mdac update is that I have never had a problem with the mdac getting installed using this;

start /wait %systemdrive%\install\Hotfixes\Q823718.exe /Q /C:"dahotfix /Q /N"

but I know a few others have. thx for the info though.