Software Diagnostic tests for hardware

There are several diagnostic and maintenance tools provided in most of the operating systems. Some of the most important diagnostic tools are:

1. Disk Error checking. Or Scan Disk
2. Disk Clean up.
3. Disk Defragmenter

1. Disk Error-Checking

Check Disk (Chkdsk.exe) is a utility which verifies the logical integrity of a file system. In the event of the utility encountering logical inconsistencies in file system data, it will perform the necessary actions to repair the file system data.  The equivalent utility in earlier versions of Windows was referred to as Scan Disk.

The following procedure describes how to perform error-checking of a hard drive under Windows XP:

1.  Launch disk error checking by double-clicking My Computer, right clicking the hard disk drive you want to have checked, clicking Properties and Select the Tools tab.

Click Check Now.

The Windows 98 equivalent to the Windows XP disk error-checking program (chkdsk.exe) is the ScanDisk utility, accessed via Start > Programs > Accessories > System Tools.

This provides options for performing either a standard or thorough test of the specified disk volume. The former checks files and folders for errors, while the latter additionally scans the disk for physical errors.  Select the required option for the areas of the disk to be scanned. ScanDisk usually cannot repair errors in the system area of a disk. If such errors exist, your disk probably needs to be replaced.

Specify whether or not you want ScanDisk to verify that sectors can be read from and written to, and/or have the utility repair hidden and system files on your disk.

b) A dialogue box showing the Check disk options is displayed.Select the options as appropriate and click Start.

c) If either of the Check disk options are selected, you'll be notified that the check cannot be performed immediately, and offered the opportunity to schedule this to occur the next time your system is booted

d) Click Yes to so schedule the disk check.The next time you start your system, the chkdsk.exe utility will be run prior to Windows being loaded, examining all the metadata on the volume in five
separate stages:

Stage 1: Verifying file data
Stage 2: Verifying security descriptors
Stage 3: Verifying indexes
Stage 4: Verifying files
Stage 5: Verifying free space.

When the utility finishes, Windows will continue to load as per a normal system start-up.

2. Disk Cleanup

The Disk Cleanup tool helps you free up space on your hard disk by searching your disk for files that you can safely delete. You can choose to delete some or all of: temporary Internet files downloaded program files, such as ActiveX controls and Java applets the Recycle Bin
Windows temporary files
optional Window components that you are not using installed programs that you no longer use.


The following provides step-by-step instructions on how to use the Disk Cleanup tool under Windows XP.

1. Launch Disk Cleanup via Start > All Programs > Accessories > System Tools. 
2. A dialogue window will appear enabling you to select the drive you want to clean up.
3. Select the required drive and click OK.
4. The specified drive is examined and the amount of space that can be potentially freed up calculated.
5. The results, showing the amount of space that can be recovered by deleting different areas and files, are then displayed on the Disk Cleanup tab. 
6. One of the options that isn't checked by default is Compress old files. Checking this will result in files that haven't been used for a while being archived. With this item selected in the list. 
7. Click Options to set a time limit for files to be compressed. 
8. Check the boxes associated with the items you want to delete and click OK. The utility cleans up the specified areas and files
9. The More Options tab provides further scope for freeing up disk space.

3. Disk Defragmenter

In older file system architectures, if a file could not be stored contiguously, it could not be saved to the disk. Newer architectures intentionally divide files into multiple pieces so as to make more efficient use of disk storage space.
Since files are constantly being written, deleted, and resized, fragmentation is a natural and ongoing occurrence. However, it is also one that has significant performance implications. When a file is spread out over several locations, it takes longer to read and write. In fact, the effects of fragmentation can be more widespread than that, causing long boot times, random crashes and system freeze-ups. 

DefragmentationThe process of removing wasted space between fragments on a hard disk by reorganizing and rewriting files is called Defragmentation.

Defragmentation is a time-consuming process, the more so the greater the extent of fragmentation. It is therefore important to terminate any programs, including those running in the background like firewalls and anti-virus programs - before starting the defragmentation process. Failure to do so will mean that it is constantly interrupted, adversely impacting the time the process takes possibly to the extent of it failing to complete.

The following describes how to subsequently defragment your hard drive under Windows XP.
Note that we cannot defragment a hard disk that is completely full, and that the less free space there is, the longer defragmentation will take. This is because the defragmentation utility need some room in which to temporarily store fragments as it reassemble files.

If the hard disk is relatively full, it is therefore good practice to run Disk Cleanup before attempting to defragment a drive.

1. Launch the Defragmenter Tool, either through 
2. Start > Programs > Accessories > System Tools .......or by double-clicking My Computer, right-clicking any hard disk drive, clicking Properties ...... and selecting to Tools tab
3.  The resulting display will list your hard disk drives, showing the capacity and amount of free space for each. Select the drive you want to defragment andclick Analyse.
4. The drive is scanned and a visual representation of the degree to which it is fragmented displayed. 
5.  Depending on the the results of the analysis, you will be advised as to whether of not the volume should be defragmented. 
6.  Even if it's not strictly necessary, you can choose to Defragment.
7. The length of time the defragmentation takes will depend on the size of the drive, the degree to which it's fragmented and the amount of free space it has. Be prepared to to allow it to run for several hours, if necessary. 
8. The dialogue box will indicate when the process is complete 
9. A visual representation of the now defragmented drive is shown above. 

 Click View Report

Figure below shows a typical defragmentation report.