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From: guy@auspex.auspex.com (Guy Harris)
Newsgroups: comp.windows.x
Subject: Re: Macintosh vs. X windows
Message-ID: <5571@auspex.auspex.com>
Date: 29 Jan 91 19:04:37 GMT
References: <9101281627.AA09545@fis1.shearson.com>
Organization: Auspex Systems, Santa Clara
Lines: 30

>	However on the other hand, unlike the Macintosh *proprietary* 
>	approach, X was designed to be policy-free and only specified the
>	mechanisms.  Also, portability among different machines, operating
>	systems and even networking protocols was a design choice that
>	the Mac ignores (probably more of a business decision than a technical one).
>	If you specify policy in the window system, you probably
>	can get away with less code in your toolkit and less complexity,
>	but you lose the portability that allows a client pgm that was 
>	developed on a Sun to be executed on a Cray and connected 
>	to an X server on, say a Macintosh.

At the purely technical level, I don't see what being policy-free has
to do with portability.  Were you to combine the policy-free (mostly) X
code with some particular toolkit+window manager, say, that provided
policy, and got that combination ported to the Sun and the Cray, then if
that combination didn't depend on server features not present on the Mac
server, you'd have the same portability as above.

Note also that the WM networked window system done at Carnegie-Mellon as
part of the Andrew project specifies more policy than does X - the
equivalent of the "window manager" functions are built into the server,
as is support for menus - and it's been ported to more than one platform
as well, although it hasn't caught on (I don't think the source was
freely available the way the X source was, although the Andrew
*toolkit*, which runs atop WM or X and perhaps other window systems, is
available).

It may be that part of what got X *ported* to that many platforms was
that, by not specifying policy, it didn't tick off as many vendors -
although a lot of the porting wasn't done to make an official product.