DSDT.aml (Differentiated System Description Table) is a file used to tell OS X how to locate and enable features of your computer mainboard without checking of BIOS. It can be placed at the root of your system hard drive or in /Extra folder which depends on your installation method.
It’s possible to tweak Os X system in all sorts of ways by changing lines of code in the DSDT.aml file. Unfortunately, you can’t just open this file in TextEdit. First you must extract your DSDT.aml, convert it to DSDT.dsl, then edit it and recompile it to DSDT.aml. To make it easy there is a GUI application that allows you to do all of this in one editor.