This site explains how BIOS interrupts work a little more in depth, including DOS vs BIOS interrupts and the interrupt descriptor table.
This is the most complete list of BIOS interrupts I’ve come across to date. It’s split across a bunch of zip files and stored in plain text files, which makes reading it a little bit of a pain, however it documents every little nook and crannie, often covering something vital that’s simply left out of other documentation.
Wikipedia, believe it or not, actually has one of the more complete lists of BIOS interrupts I’ve come across. They also have an excellent article about the interrupt descriptor table.
Interrupt descriptor table – This is a location in the memory where pointers to all the interrupts are stored. When an interrupt is called, the BIOS retrieves the pointer location from the interrupt descriptor table and executes the code at that memory location.