Version 3.2

The Original File Allocation Table Monitor

by Easy Desk Software

NOTE: You should run Scandisk for Windows at least once a week even if FATMon is always working.

Setting up FATMon
Skipping a Drive to Watch
What is the File Allocation Table


What is the File Allocation Table

The File Allocation Table of contents of a computer disk contains the information that determines what sectors are used for what file. The File Allocation Table (also know as FAT), is located in the first 63 sectors of your hard drive. You visually cannot see this. The first 63 sectors is known as the data sector.

The FAT file system revolves around the File Allocation Table for which it is named. Each logical volume has its own FAT, which serves two important functions: it contains the allocation information for each file on the volume in the form of linked lists of allocation units and it indicates which allocation units are free for assignment to a file that is being created or extended.

The FAT contains the information of each file or directory name, what sector the file starts in, and how large the file is. If this table (Table 1) becomes corrupted, or what is known as disk errors, there is a second (backup) table (Table 2) available for programs like Scandisk to use to fix the FAT (Table 1).

When the system crashes, no data is lost. However, a FAT system may have removed disk area from the chain of free space, but may not yet have assigned it to any permanent new data set. The CHKDSK or SCANDISK utility examines the FAT table to determine the status of every record on disk. The records which are not part of any data set may be returned to the free space chain. If Scandisk is not run to make these repairs and the chain is broken, sectors and cluster can become lost (unidentified). The file then is a corrupted file or becomes marked as free space. If enough chains are broken or lost, then you will probably have to format the drive.

FATMon watches for changes in the FAT while you are in Windows and allows you the make the needed repairs before shutting down only then to find out that you have loss files or even your operating system.

To learn more about FAT visit our site page File Allocation Table at http://www.easydesksoftware.com/fat.htm

Setting up FATMon

FATMon will not only notify you when the FAT changes, but is also programmed to notify you when any of your Resources reach a level lower then 15%.

1) To change the setting on FATMon at any time right click its icon in the system tray and select Setup. The program to select fix disk errors must be either Scandisk for Windows or a third party program that performs the same functions. FATMon does not check the FAT for errors, it checks for changes in the FAT. When FATMon pops up and tells you that the FAT has changed, this does not mean that there is a disk error. It merely mean that the FAT has changed. If you have not added, deleted or created a new file then there probably is a disk error.

2) The number entered in the window that says "Notify me when the File Allocation Table changes more than" should be set to the lowest number possible. If FATMon gives you messages that the FAT has changed too often you will need to reset this entry to a higher number. This number determines the size of change in the FAT before notifying you. The best way to set this number is too estimate how much free space is on your system do you use or gain each day. Set this number to the average. Do not count the Swap file. Reminder when you download a file, the download is creating a file so if you download everyday consider the size of the files you are downloading.

Example: If you do a lot of scanning and save the scans to files (lets say more than 200 Megs a day); you may want to set this number to the maximum value of 200. If you scan and save one or two files a day, you may want to set this number to 30. If you use your computer to create letters, then you should leave the recommended setting of 3. The minimum allowable setting is1.

3) The "Check the FAT every" window determines how often FATMon checks for FAT changes. The process only takes a second or less to run. The recommended setting is set to 120 second intervals (every 2 minutes). The maximum value allowed is 999 seconds. This feature is available for those users that do work that uses a lot CPU usage constantly. Allowing the CPU to do your work without being interrupted too often.

4) The check box "Do not notify me if the FAT reports a decrease in available clusters" should be checked ONLY if you are not worried about a virus or Trojan. A virus or a Trojan can attack the FAT or create thousands of files on you hard drive to crash it. Normally when the FAT becomes corrupted, clusters are marked as free space; but occasionally clusters are marked as used. If this happens it can also corrupt the files that the cluster pointers to.

6) The log notifications check box enables FATMon to keep a log for you. The file name is Fat.log and is kept in the same folder as FATMon.exe. This log file should assist you in determining the size of change you want to be notified with. Remember it is better to be warned of a change 3 or 4 times a day then it is to have to format your hard drive.

7) The last item you may wish to setup for FATMon is a minimum Swap File size. If you set a minimum size you will not get the message that the Swap File size has decreased when you boot up. Set a Swap File size in KB that is the current size of your Swap File. Normally it is in your Windows folder and is named Win386.swp. In NT it is normally in the root directory and named Pagefile.sys. You can use our software product QikFix's Memory Utilization utility to set this up for you precisely. Creating a minimum Swap File size will help keep the Swap File from becoming fragmented, improving performance.

8) FATMon will now start automatically every time you boot to monitor the FAT. If you wish to uninstall FATMon you MUST first use the uninstall feature on the "About" FATMon window. You can access the "About" window by right clicking the FATMon icon in the system tray. FATMon creates an entry in the Registry in the Run key, that tells Windows to start FATMon whenever Windows boots up.

Skipping a Drive to Watch

To have FATMon not watch a drive you need to add an entry to the Registry Key HKEY_CURRENT_USER\Software\VB and VBA Program Settings\Fatmon\NoWatch . To add an entry, Right click the folder NoWatch in the right hand pane, select New and then String Value. Change the Value Name by right clicking it and selecting Rename to the Drive letter you do not want FATMon to watch. Example: "E" (without the quotes). Then right the "E" and select modify, and enter a "1" (without the quotes). Your entry should look like the following after you are done:
Name                                                            Data
E                                                                     "1"
FATMon will no longer watch the E drive.