Tech Talk (10/02)
More Tools for WinXP
by Brian K. Lewis, Ph.D.*
Member of the Sarasota Personal Computer Users Group, Inc.
Last month's article on WinXP didn't cover all the available tools. However, one it did cover, Automated System Recovery (ASR), had some incomplete information. The ASR may backup up your applications and data. When you run the ASR Wizard, one window tells you very specifically that you will need to run the Backup application after running the ASR Wizard to save your data. However, an IT tutorial on the Microsoft web site states: "The wizard backs up the system state, system services, and ALL DISKS associated with the operating system components.", (emphasis added.) So, if your applications and data all reside on the C drive with the components of Windows XP, they should be backed up along with all the system state information. The questions remain however, about the Restore process. You should note that in any restore process with ASR, the primary drive will be reformatted. Although Microsoft specifies that data files will not be restored, in the same breath they state that: "ASR will read the disk configurations from the file that it creates and restore all of the disk signatures, volumes and partitions on, at a minimum, the disks required to start the computer." Note that this does not specifically include data files, but it is not clear to me whether restoring volumes and partitions includes applications and data files. If you plan on using ASR to restore your system in case of a failure, I would proceed with caution. At a minimum, keep a separate backup of all your data files.
Previous versions of Windows used Scandisk to verify file and disk surface integrity. In WinXP, this has been replaced with an updated version of ChkDsk. This application can be run in command line or in graphical mode. However, if it is run without any parameters, it runs in read-only mode. It also functions differently depending on whether your disk is formatted with FAT32 or NTFS.
To run Chkdsk from the graphical interface go to Windows Explorer or My Computer and right click the drive you wish to check. Select Properties, then Tools. In the Tools window you have three choices: Error Checking, Defragmentation or Backup. When you click on "check now", the next window gives you two options: "automatically fix file system errors" and "scan for and attempt recovery of bad sectors". Do not check either of these boxes unless you have already received a Windows error message indicating there is a file or directory problem that can be fixed by Chkdsk. When you run Chkdsk without these parameters, it runs in "read-only" mode and can not repair any errors if finds. However, it will report if errors are found. If you check either of the options and if you are checking your boot drive, you will get a message indicating that Chkdsk can not lock the drive and can not run. The message will also ask if you want the volume checked the next time the system boots. If you select "yes", then an application called Autochk will run when the system is rebooted. NOTE: once Autochk starts running, there is no provision that allows it to be canceled. It MUST run to completion no matter how long that takes. During this time the computer will be unavailable for your use. After Autochk is finished, the computer will automatically restart.
With the repair options selected, it may take anywhere from several hours to several days for Chkdsk (Autochk) to completely verify the integrity of the drive and disk files. Admittedly, the longest period of time will involve systems acting as servers. However, if there are no known problems on your drive, you probably don't want to take the time necessary to run Chkdsk with either of the options. When running the read-only version of Chkdsk, the time required to analyze the disk is only minutes. It took less than 5 minutes to verify my 40 Gb drive.
On an NTFS drive, Chkdsk will show 3 phases during the check process. Phase 1 is the checking of the file record segments in the Master File Table (MFT). There is a record segment for every file and directory on an NTFS volume. In Phase 2 Chkdsk examines each of the indexes (directories) on the volume and verifies that every file and directory represented by a file record segment in the MFT is referenced by at least one directory. Chkdsk also confirms that every file or subdirectory referenced in each directory actually exists as a valid file record segment in the MFT and checks for circular directory references. Chkdsk then confirms that the time stamps and the file size information associated with files are up-to-date in the directory listings for those files. In Phase 3 Chkdsk examines each of the security descriptors associated with each file and directory.
On a FAT32 volume, Chkdsk verifies file integrity, checks for lost cluster (allocation units) and cross-linked files. This occurs in a single operation.
The Disk Defragmenter program has also been changed in XP. There is a graphical version that allows you to analyze the amount of defragmentation. A sample screen shot taken from the Microsoft TechNet is shown below:
Microsoft refers to this application as the "snap-in". To open this snap-in, go to Start - Run and type in dfrg.msc, then click on OK. This brings up the screen shown above. Then click on the analyze button. If the analysis indicates that the volume is more than 10% defragmented, Disk Defragmenter will recommend that the volume be defragmented. If the result is less than 10% defragmented, you can either defragment or simply view the report.
By comparing the "Estimated disk usage before defragmentation" band to the "Estimated disk usage after defragmentation" band, you can see the expected improvement in your volume after defragmenting. The defragmentation report provides further details on the fragmentation state of the volume. You should analyze your disk volumes regularly and defragment them when Disk Defragmenter recommends it.
For best results when defragmenting disk volumes, follow these tips:
Before defragmenting a volume, delete any unnecessary files, such as temporary files. You can delete unnecessary files by using "Disk Cleanup". To access "Disk Cleanup" go to "My Computer" and right click the drive you wish to clean. Select "Properties" from the menu and then click the "Disk Cleanup" button. If you are using WinXP professional, be sure you are logged on as an Administrator.
Defragment a volume before you add a large number of files to the volume, such as before you install programs. This ensures that the files occupy contiguous space and do not become fragmented after you add them.
Defragment a volume after you delete a large number of files from the volume.
Always defragment volumes during periods of low system activity. In other words, close active programs such as your screen saver, firewall and anti-virus software. Set your power savings to never turn off your monitor or your disk drives. If you are connected to cable or DSL, turn off the power to your modem or disconnect the cable.
Windows XP monitors the files that are used when the computer starts and when you start applications. By monitoring these files, Windows XP can prefetch them. Prefetching data is the process whereby data that is expected to be requested is read ahead into cache memory.
Prefetching boot files and applications decreases the time needed to start Windows XP and to start applications. Prefetching is further improved if the files are located next to each other on the outer edge of the disk. Windows XP optimizes the location of boot files and applications when the computer is idle. The optimization process occurs in the background and lasts only a minute or two; you might hear the hard disk being accessed when optimization occurs. After the initial optimization takes place, subsequent optimization occurs, at most, every three days, according to Microsoft.
When you run the Disk Defragmenter tools that are included with Windows XP, they can perform any optimization updates that are scheduled to take place during the next idle period. The Disk Defragmenter tools do not disturb the existing layout of optimized boot files and applications. Also, there are files that can not be moved during optimization or defragmentation. In the figure you will note there is a non-movable section in the bar. This is primarily the paging or swap file that Windows sets up on your hard disk. It also includes the master file table on NTFS volumes and other non-movable boot files.
As with any other Windows tools, always use caution when running any of these applications.
*Dr. Lewis is a former university and medical school professor. He has been working with personal computers for more than thirty years. He can be reached via email at brian_klewis@hotmail.com or voice mail at (941) 925-3047. :
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