Re: CDA vs. NDA vs. CDEV

[jmk3@crux3.cit.cornell.edu (Jay Krell)]

The capabilities of control panel's did not change much in System 6.
If I recall correctly, the only changes are they now have access to the edit
menu and their data forks are no longer reserved. You can also have TextEdit
control's in the About box now, since the NDA makes sure TextEdit is active.
 
One of the biggest diff's between cdevs and ndas is that, w/o some extra work,
ndas sit around in memory and cdevs do not. This can be reversed and combined.
I don't know about the network related cdevs, but I believe of all cdev's Apple
ships, only Sound keeps stuff in memory. The Control Panel NDA eases the
programmers job in terms of presenting an interface; it deals with a lot of the
overhead NDA's must deal so that most of interface code in a cdev is just
dealing with hits to controls.
 
According to Apple, the cdevs folder was not renamed in System 6 because some
cdevs rely on the name, though that is stupid. It is fairly simple to not rely
on fixed pathnames, just do, like, GetRefInfoGS(GetOpenFileRefNum()).
 
Anything that can be done as an NDA can be done as a CDev and anything that can
be done as a CDev can be done as an NDA.

--
  --Jay, jay.krell@cornell.edu