A DDK is a
Driver Development Kit. It's a more
specific form of an
SDK, usually for
Kernel mode development on a non-
open source system.
Microsoft is the only
vendor off the top of my head that produces (or more specifically referrs to it as) a DDK. (
msg me or add-on if I am incorrect).
Apple does produce a
Kernel module loading system for
OS X, and i think that driver developement under earlier
Mac OS's just used a more
cryptic set of Extension
APIs.
With the MS DDK, you get a
build environment (which still requires the
cl compiler),
documentation, and
how-to's for producing drivers for each major
OS release. There are also HAL
toolkits for NT (if you are brave enough to write your own HAL). It's a
hairy process and requires a
serial cable for
two machine debugging using
windbg.
Apple's IO Toolkit, and Kernel toolkit also require two machine debugging using
arp over
ethernet and remote
gdb.