Managing Page Files

Microsoft® Windows® 2000 Scripting Guide

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The Windows 2000 operating system supports virtual memory. With virtual memory, a special file on a hard disk (known as a page file or a swap file) is used to supplement the physical memory installed on a computer. When a computer begins to run low on physical memory, data can be "swapped out" to the page file. This has the following advantages:

• It frees up physical memory.
• It makes it relatively fast and easy to retrieve the data, because the system knows exactly where to look for it.

Page files and virtual memory are extremely important to fast and effective computing. Without page files, computers would need double or triple the amount of physical memory in order to achieve the same level of performance.

System administrators need to review page file settings as part of a management routine that ensures that page files have been sized optimally and that each drive on a computer has its own page file. In addition, page file usage should be monitored on a regular basis; excessive paging often means that a computer has too little physical memory to carry out the tasks assigned to it.

WMI has several classes that can be used to help manage page files, including the Win32_PageFile class, which returns detailed information about each page file on a computer. Table 10.10 shows several of the key properties of this class.

Table 10.10   Win32_PageFile Properties

Property	Description
CreationDate	File creation date.
CSName	Name of the computer system.
Description	Description of the object.
Drive	Drive letter (including colon) of the file.
EightDotThreeFileName	MS-DOS compatible file name for this file.
FileSize	Size of the file (in bytes).
InitialSize	Initial size of the page file, in megabytes.
InstallDate	Date the page file was created.
MaximumSize	Maximum size of the page file as set by the user. The operating system does not allow the page file to exceed this limit.
Name	File name of the page file.
Path	Path of the file. This includes leading and trailing backslashes.

Scripting Steps

Listing 10.19 contains a script that enumerates the properties of all the page files on a computer. To carry out this task, the script must perform the following steps:

1. Create a variable to specify the computer name.
2. Use a GetObject call to connect to the WMI namespace root\cimv2, and set the impersonation level to "impersonate."
3. Use the ExecQuery method to query the Win32_PageFile class.

   This returns a collection of all the page files on the computer.

4. For each page file in the collection, echo the values of such properties as the file name, current file size, initial file size, and maximum file size.

Listing 10.19   Enumerating Page File Properties

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strComputer = "." Set objWMIService = GetObject("winmgmts:" _     & "{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2") Set colPageFiles = objWMIService.ExecQuery _     ("SELECT * FROM Win32_PageFile") For each objPageFile in colPageFiles     Wscript.Echo "Creation Date: " & objPageFile.CreationDate     Wscript.Echo "Description: " & objPageFile.Description     Wscript.Echo "Drive: " & objPageFile.Drive        Wscript.Echo "FileName: " & objPageFile.FileName        Wscript.Echo "FileSize: " & objPageFile.FileSize        Wscript.Echo "InitialSize: " & objPageFile.InitialSize     Wscript.Echo "InstallDate: " & objPageFile.InstallDate     Wscript.Echo "MaximumSize: " & objPageFile.MaximumSize     Wscript.Echo "Name: " & objPageFile.Name        Wscript.Echo "Path: " & objPageFile.Path    Next

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