What is INT 21h?

Question

Inspired by this question

How can I force GDB to disassemble?

I wondered about the INT 21h as a concept. Now, I have some very rusty knowledge of the interna

Answer 1

Ralph Brown's interrupt list contains a lot of information on which interrupt does what. int 21, like all others, supports a wide range of functionality depending on register values.

A non-HTML version of Ralph Brown's list is also available.