Why does defragmentation on Windows 98 and Windows Me take time?

Why does defragmentation on Windows 98 and Windows Me take time?
or
How does defragmentation on Windows 98 and Windows Me differ from that of Windows 95?

Defragmentation takes time due to the process of logging files and rearranging files in the hard disk drive. And, defragmentation takes time if it's being run for the first time.

--Precautions of defragmentation--
1. Finish any running software, including the screen saver and stay-resident programs.
2. Disable the settings of the infrared monitor.

Repeating to write data to and reading it from the hard disk drive generates the fragmentation of files. That is, files are stored to discontiguous files. Due to this fragmentation, the hard disk has to move its head on various positions to read one file, which leads to longer time for accessing data. To avoid this, files must be re-written to the contiguous clusters and defragmentation is the tool for doing it.

Using IALA (Intel Application Launch Accelerator) developed by Intel, Defragmenter of Windows 98 is designed to arrange files such as DLL that are read together with application software in the contiguous clusters to minimize seek and to accelerate the startup of application software.

Furthermore, the program called [TASKMON.EXE] that is referred to at the startup time of applications always monitors the startup of application software to log the file and cluster information of each application in the file. When defragmentation is carried out, Defragmenter rearranges files necessary for the startup of application software, referring to this log file.
* The log file is created at the second startup time of the software application.

1. Defragmenter tries to optimize the frequently used files in the hard disk drive. Therefore, if software that tends to start automatically in the middle of defragmentation is in the task bar, defragmentation may have to be repeated sometimes.
- To finish the stay-resident programs in operation, click [Run] and enter "MSCONFIG.EXE" in the text box to start [System Configuration Utility].
- Disable the stay-resident programs on the [Start Up] tab of [System Configuration Utility].

2. When the settings of the infrared monitor are enabled, the monitor checks the existence of available infrared devices around it at intervals of a few seconds (3 seconds in principle) to create a log. Whenever data is written to the log (change of the contents of the hard disk drive) in the middle of the execution of defragmentation, defragmentation has to be repeated from the beginning.
- Select [Infrared Monitor] on [Control Panel]
- Clear the [Enable infrared communication] check box in the [Options] tab of [Infrared Monitor].

"McAfee VShield" will cause the same symptom if a user has made the settings to execute Schedule.