Each request to Active Directory to add, modify, or delete an object or attribute is treated as an individual transaction.

Active Directory uses the following files: 
	NTDS.DIT - The AD database file. DIT = Directory Information Tree
	           Located by default: %SYSTEMROOT%\NTDS\NTDS.DIT

	EDBnnnn.LOG - The AD transaction log file. The maximum size of this
	              file is 10mb. As the size grows over 10mb, a new log
	              file is created with the nnnn value progressing. The
	              current file always being used it EDB.LOG.

	EDB.CHK - Used by AD database engine to track the data which has not
	          yet been written to the database NTDS.DIT. It is a pointer
	          to the memory location in the hardware.

	RES1.LOG - Used to reserve disk space in the event that the hard
	RES2.LOG   disk is low on free space. 20mb total reservation.
Active Directory Database Modification Process
  1. ESE loads the data to be modified into memory as pages. This prevents multiple disk writes while modifying a large number of objects.
  2. ESE logs transactions to be made in EDB.LOG.
  3. ESE writes the object modifications (in memory) to the NTDS.DIT database file.
  4. ESE updates EDB.CHK to indicate that the transcations were successfully written to the database file.