On Sun, 8 Dec 2002 03:53:00 +0200 (IST)
guy keren <[EMAIL PROTECTED]> wrote:
> i noticed there are various environment variables that allow overriding
> various settings for the resolver library, but they don't seem to allow
> enough control to actually override such settings
I'd like to (ab)use your question to general "config" mechanisms
available, and some comparisons:
Environment variables:
- Per-process
- Inherited (so we can make them "global")
- No change (from outside) after process startup
- Flat name-space (not scaleable)
Global config files:
- Global
- Change may/may-not affect after process startup
(e.g: SIGHUP to daemons etc.)
- Managed case by case (each with its own rules)
- Arbitrary types/ammounts of data
Global config database (e.g: Windows Registry, GNOME GConf):
- Global
- Change affect processes even after process startup
- Centralized management (but luckily, GConf doesn't
force you to have all config in one big file)
- Hierarchical namespace (scaleable)
After looking at the pros/cons of each mechanism, I think it will be
illuminating to present another very old mechanism:
The X toolkit resource database:
- Global
- Hierarchical namespace (scaleable)
- The key heirarchy permit overrides:
- per type of application (window class)
- per instance of application (window)
- Centralized managment (xrdb(1)), but database
may be spread at multiple locations (along
the XAPPRESPATH and in the Xserver as well)
- Application may allow changes to occur after
startup (instantiation), see editres(1)
Looks like it takes most of the pros from all methods
(except of inheritance -- designed not Unix specific),
without the cons.
Now, isn't it a pitty that this mechanism is dying? Both KDE
and GNOME chose to develop their own (inferior IMHO) mechanisms.
Hopefully later GConf versions (which isn't GNOME/X specific) will
include the missing parts, so we can return to the flexibility
we had in the 80's :-)
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