The Differentiated System Description Table is the main table in the ACPI part of a computer's BIOS.
The Advanced Configuration and Power Interface (ACPI) defines a large number of tables that provide the interface between an ACPI-compliant operating system and system firmware. These allow description of system hardware in a platform-independent manner in ACPI Machine Language (AML).
The problem is that OS X has an incomplete ACPI implementation which supports only a subset of DSDT. Modifying the DSDT allows the user to better support their hardware. For example, fixing Time Machine and the UUID 35 error is possible after modifying the DSDT.
To patch your DSDT, you must either use a new table file that someone else has provided, or extract and modify your own. Then tell your bootloader to use the new DSDT file instead of the BIOS.
Extracting from your BIOS
Some tools will extract and modify your DSDT automatically. If you want to extract the DSDT manually, you will have to use the command line.
You can extract the DSDT that is built in to your motherboard with a command-line tool that comes with OS X. The command
ioreg will display the I/O Kit registry, which is more than we need.