Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!samsung!uunet!ateng!chip From: chip@ateng.com (Chip Salzenberg) Newsgroups: news.groups Subject: Hierarchies Message-ID: <25684CEF.26422@ateng.com> Date: 20 Nov 89 19:13:49 GMT References: <6951@ficc.uu.net> <11414@cbnews.ATT.COM> <4362@hplabsz.HPL.HP.COM> Organization: A T Engineering, Tampa, FL Lines: 31 According to sartin@hplabsz.HPL.HP.COM (Rob Sartin): >In some areas we see various modifications to systems to work around the >fact that hierarchies don't model reality well. [...] >The Unix filesystem has symbolic links and hard links. >C++, in its evolution from 1.2 to 2.0, added multiple inheritance >which (at least) made inheritance a DAG instead of a tree. > >The news software and users needs a method for jumping out of the system >(of hierarchies) when it appears to be inadequate. Actually, the news software does provide mechanisms for bypassing the news hierarchy when necessary: 1. Crossposting. Rather like Unix hard links, in that an article exists equally in all the named groups. 2. Aliasing. The news administrator may set up an alias for a newsgroup. Depending on the news version, an alias may or may not modify the article header. Rather like Unix soft links. Sample aliases: mod.sources comp.sources.unix sci.aquaria alt.aquaria 3. Followup-To. Says that this article may be cross-posted, but continued discussion should go to a particular place. I wonder what further escapes from the hierarchy are needed. -- You may redistribute this article only to those who may freely do likewise. Chip Salzenberg at A T Engineering; or "Did I ever tell you the Jim Gladding story about the binoculars?"