On Windows XP, programmatically set Pagefile to "No Paging File" on single c: drive

Question

I'm trying to write a C#/.NET application that optimizes the hard drives for our XP workstations

1. Set pagefile to "No paging file"
2. Reboot
3. Run a defrag utility to optimize the data and apps
4. Create a contiguous page file
5. Reboot, run pagedefrag from Sysinternals

I'm really struggling with #1. I delete the following key: SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PagingFiles

Upon reboot, the System Control Panel shows "No page file", but c:\pagefile.sys still exists and its in use by the SYSTEM process so I can't delete it and I can't optimize HD. I tried using PendingFileRenamingOperations and that bombs out too. I tried using WMI: Win32_PageFileSetting, but that only lets you set sizes (not zero--defaults to 2MB).

Of course, if I do the manual steps outlined above, it works.

I think I need an API call to make this happen.

Neodarwinism

It appears the paging file is in use for one more boot cycle. On the second reboot the file is no longer in use. This is for Windows 7. – Fribble

Answer 1

Look at Delete or DeleteEx methods of the Win32_PageFile class:

The class has been deprecated but since you're talking about Windows XP, maybe it wasn't deprecated then.

Exorcism

Answer 2

Actually, the mistake I made was delete the registry key.

What I had to do is set the multi-string value to something like

rk.SetValue("PagingFiles", new string[]{""}, RegistryValueType.MultiString)

Good luck!

Neodarwinism

Answer 3

You can modify registry in order to change pagefile settings.

They are stored in the following registry's key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

PagingFiles value contains values in the 'PageFileLocation MinSize MaxSize' format (i.e. 'C:\pagefile.sys 1024 2048') -- you can find more on that in this article.

Broom

Actually, I'm trying to get rid of the pagefile (temporarily). I know there's a WMI call that does what you're saying, but XP says that's a no no (setting min and max to zero) and resets it to 2MB instead. – Neodarwinism

@NBPC77: Possibly API restricts removing all page files. I do not have a pagefile on my system (8 GB of RAM is quite enough) and that PagingFiles value consist of two empty lines. – Broom