Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!dlyons
From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: Re: deleting DA's from memory
Keywords: DA, CDA, NDA, Desk Accessories, System Software
Message-ID: <32347@apple.Apple.COM>
Date: 10 Jun 89 02:37:47 GMT
References: <8905272100.AA01113@obsolete.UUCP> <31983@apple.Apple.COM> <678@madnix.UUCP>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 30

In article <678@madnix.UUCP> jason@madnix.UUCP (Jason Blochowiak) writes:
>How about something like: If the first word that's pointed to by both
>the CDA Entry and ShutDown addresses in the CDA header is $0000, then the CDA
>is considered removeable. Perhaps something similar for the NDAs.

Remember that any new format invented needs to do something reasonable under
previously released system disks.  Having the old systems execute BRK
instructions for new DAs wouldn't be terribly reasonable. :-)  (The *new*
system could check for the $0000, but the old systems can't be changed to
do that.)

>                                                                  I don't
>understand why they didn't put a "supported calls" count in the headers - then
>there could be a "are you removeable?" call to the DA.

I personally think that sounds like a nifty idea--but any new standards for
DA formats would have to be compatible with the existing formats and would
have to come from the appropriate group within Apple.

>    jason@madnix.UUCP, methinks.     Formerly blochowi@garfield.cs.wisc.edu
>			"It beats working" - Harrison Ford

 --Dave Lyons, Apple Computer, Inc.          |   DAL Systems
   AppleLink--Apple Edition: DAVE.LYONS      |   P.O. Box 875
   AppleLink--Personal Edition: Dave Lyons   |   Cupertino, CA 95015-0875
   GEnie: D.LYONS2 or DAVE.LYONS         CompuServe: 72177,3233
   Internet/BITNET:  dlyons@apple.com    UUCP:  ...!ames!apple!dlyons

   My opinions are my own, not Apple's.