Linked by Thom Holwerda on Mon 18th Jun 2007 21:54 UTC, submitted by ericvh
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Member since:
2006-04-21
Could you elaborate? I don't quite understand what you mean about too much policy within the mechanism. I always wondered if X could do with a little more policy laid down.
I mean this: UNIX and the X Window system (which isn't UNIX specific) both specify that the system should have "a user interface" (respectively, the shell and a window manager and widget toolkit) (= mechanism), but don't specify how it should work or what it should look like (= policy): Thus you get bash and zsh and csh and tcsh and scsh et al., and GNOME and KDE and WindowMaker and FVWM and blackbox, or Motif and Athena et al. Of course both UNIX and the X Window System *do* both implement a *little* policy, but not much: Filesystem workings (10 permissions bits, hierarchical directories and so on) on the one hand, transmission strategies (via TCP/IP or DECNET) on the other, but a lot less than a system like, say, Windows, MacOS or Plan 9. You can get shells for Windows (such as LiteSTEP), and maybe even for MacOS X and Plan 9, but by necessity they mung the inner workings of the environment a lot more than stuff like GNOME or KDE needs to - all else being equal, for example, it would probably have been significantly harder to write a reparenting* window manager for Windows than it was for X11.
*Where the WM takes control of the window positioning from the lower levels of X.