Windows 2000 introduces a new type of disk partitioning scheme that is
managed by a component called the Logical Disk Manager (LDM). Basic
disks implement standard DOS-style partition tables, whereas Dynamic
disks use LDM partitioning. LDM partitioning offers several advantages
over DOS partitioning including replication across disks, on-disk storage
of advanced volume configuration (spanned volume, mirrored volumes,
striped volumes and RAID-5 volumes). My March/April two-part series on
Windows NT/2000 storage management in Windows 2000 Magazine describes
the details of each partitioning scheme.
Other than the Disk Management MMC-snapin and a tool called dmdiag in
the Windows 2000 Resource Kit, there are no tools for investigating the
internals of the LDM on-disk database that describes a system's
partitioning layout. LDMDump is a utility that lets you examine
exactly what is stored in a disk's copy of the system LDM database.
LDMDump shows you the contents of the LDM database private header,
table-of-contents, and object database (where partition, component and
volume definitions are stored), and then summarizes its finding with
partition table and volume listings.
Installing and Using LDMDump
To use LDMDump simply pass it the identifier of a disk.
Usage: ldmdump [- ] [-d#]
Parameter
Description
-
Displays the supported options and the units of measurement used for output values.
-d#
Specifies the number of the disk for LDMDump to examine. For example, "ldmdump /d0" has LDMDump show the LDM database information stored on disk 0.
How it Works
There are no published APIs available for obtaining detailed
information about a disk's LDM partitioning, and the LDM database format
is completely undocumented. LDMDump was developed based on study of
LDM database contents on a variety of different systems and under
changing conditions.
More Information
For more information on the LDM on-disk structure, see:
Inside Storage Management, Part 2, by Mark Russinovich, Windows
2000 Magazine, April 2000.
This module explores file system fragmentation and the tools that you can use to reduce fragmentation. Students will learn how Windows can compress files to take up less space on the hard disk.