Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!hsdndev!dartvax!news From: Jim.Matthews@dartmouth.edu (Jim Matthews) Newsgroups: comp.sys.mac.system Subject: Re: Why aren't 7.0 aliases real? Message-ID: <1991Apr9.133307.4740@dartvax.dartmouth.edu> Date: 9 Apr 91 13:33:07 GMT References: <1991Apr8.013825.13118@netcom.COM> <1991Apr8.174933.10818@ux1.cso.uiuc.edu> <1991Apr8.215943.6159@ux1.cso.uiuc.edu> Sender: news@dartvax.dartmouth.edu (The News Manager) Reply-To: Jim.Matthews@dartmouth.edu (Jim Matthews) Organization: Dartmouth College, Hanover, NH Lines: 35 In article <1991Apr8.215943.6159@ux1.cso.uiuc.edu>, dorner@pequod.cso.uiuc.edu (Steve Dorner) write: >> Am I missing something here? Prefs and Settings go in their respective folders >> in the system folder, right? Why would you ever want to use an alias for one? > > Suppose you never back up the drive that your system folder is on, but you > want to back up your settings files. I think this actually gets at one reason why aliases aren't handled transparently by the file system. If they were, I don't see how you could allow aliases that cross volume boundaries, or even point to other folders. The Mac file system is a forest, and allowing volumes to sprout from within other ones would greatly complicate the file system model. There's no way for PBGetCatInfo to let you know that a folder you've entered not only has a new directory id, it has a new volume refnum. Aliases to folders on the same volume can cause cycles, and break existing software. For example, my FTP client lets you upload folder hierarchies, which it traverses with a standard recursive approach. Today I know that the process will terminate; with aliases I might run into a cycle, and upload forever. The authors of archivers, virus-checkers, file-finders, etc. would be in the same boat. Plus, it would be a bit unseemly for HFS to be keeping AppleShare passwords and whatnot in file system data structures. 7.0 Aliases are more complicated and versatile than a file system directory entry, and there's room for them to grow (and become *more* complicated :-). So concientious Mac programmers will have to put calls to ResolveAlias in all the right places. And isn't doing things by hand what Mac programming is all about? :-) Jim Matthews Dartmouth Software Development --