Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!dlyons
From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: Re: Resource Forks
Message-ID: <32210@apple.Apple.COM>
Date: 2 Jun 89 18:14:50 GMT
References: <8906020837.AA22047@crash.cts.com>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 38

In article <8906020837.AA22047@crash.cts.com> pnet01!pro-sol!pro-newfrontier!pro-freedom!cdm@nosc.mil writes:
>[...]
>As for the implimentation on the GS, I understand that the file itself will
>still be the same, it will just have some header information giving the
>offsets to the begining of the data and resource forks.
>
>Carl MacDonald, programmer
>Central Point Software

Under GS/OS, files can be extended or not.  Nonextended files ("standard" files,
I think) just have one fork, the data fork, like always.  On ProDOS disks, these
have storage type 1, 2, or 3 (seedling, sapling, or tree).

Extended files have two forks, the data fork and the resource fork.  As far as
the OS is concerned, these are symmetrical--each fork can be OPENed, READ,
CLOSEd, etc. independently.

For copying and archiving, etc, this is fine, but only the Resource Manager
should try to interpret the contents of the resource fork.

Extended files which happen to be stored on ProDOS disks have storage type
5.  Only the ProDOS FST & certain disk utilities need to know the details
there.  (For the curious:  the key block for an extended file on a ProDOS
disk contains something like a miniature directory entry for each fork, 
including a storage type of 1, 2, or 3 for each fork.)

As Cray pointed out, *anything* can be stored in the resource fork; on the
Mac, even code is stored there.  Code can also be stored in GS/OS resource
forks, but it will be less common than on the Mac.

 --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.