Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!ntvax!iex!supernet!cluther
From: cluther@supernet.UUCP (Clay Luther)
Newsgroups: comp.sys.mac.misc
Subject: Re: The Mac's resource fork: does Win 3 have one?
Message-ID: <1990Jul8.075651.11009@supernet.UUCP>
Date: 8 Jul 90 07:56:51 GMT
References: <2322.268f7cca@csc.anu.oz> <2964@gmdzi.UUCP> <7705@jarthur.Claremont.EDU> <2966@gmdzi.UUCP> <23070@boulder.Colorado.EDU> <2987@gmdzi.UUCP>
Organization: Harris Adacom Corporation
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strobl@gmdzi.UUCP (Wolfgang Strobl) writes:

>This includes Windows Programmers, too. There seems to be NO DIFFERENCE
>between MS Windows and the Macintosh OS, here. Both separate
>programs into a user interface part (icons, bitmaps, menues, keyboard
>accelerators, string constants, dialog boxes, ...) and the algorithmic
>part. Both do not need a recompilation for changing the user interface.

>Wolfgang Strobl

Hmm, well, actually, code is stored in the resource fork.  The data fork is used
to store just that, data.  Actually, the way I think of it is:

the resource fork is a collection of definite objects that can be read, written,
deleted and modifed on demand without having to know the structure of the file 
or actually anything about the object itself (Since a simple call to 
GetNextResource() returns an anonymous handle).

the data fork, on the other hand, is nothing more than a stream of bytes, and
requires intimate knowledge about its structure.

However, a note:  although when we talk of a file having a data and resource 
fork, this is a misonomer:  macintosh files are virtual structures, actually
composed of two files (the forks) which are irrevocably linked.  This was a
major problem with early (still?) inceptions of the multi-finder.  MF has a 
open file limit of around 20 or so.  Each file or application you open can
cause up to 2 of the file pointers to be allocate - one for the file's or
application's resource fork, another for the data fork.  If you were in, say
a word processor and a paint program, and editing 3 files each, well that
could be 16 of your 20 pointers, leaving you only ernough room to open another
app and maybe one to three files.  And even though you might have 8 megs out
there and no where near your capacity, MF would not let you open any more files.


-- 
Clay Luther                       ..uunet!iex!supernet!cluther
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