* Ron Jensen -- 11/4/2008 1:15 PM: > On Tue, 2008-11-04 at 10:01 +0100, Ralf Gerlich wrote: > > I have already provided the arguments in favour of the three-level > > hierarchy.
Yes, we were really only arguing over whether a fourth level would be too expensive, and whether organizing files via prefixes rather than directories is a good idea. How often do we assume that files in that structure are accessed? A few dozens at startup, then one every few minutes? Performance considerations about another dir level don't make much sense to me. Especially if you consider that the harddisk has its own read-ahead cache, and that the kernel adds another layer. If you tell it to read one sector, then it will read a few of them and store them in RAM, just in case (AFAIK). The effect of that is hard to estimate, of course. IMHO writing for the machine's preferences is something that kernel and file system designers should do, not usually application designers. Microoptimization often turns out to be counterproductive later on. Having said that, I agree that adding *many* files is still a problem, though. (I've always considered file systems based on fixed numbers of inodes bad design. I'm not using that sort of stuff here. :-) > The more I hear, the less I like this idea. So I won't have ILS navaids > available if I don't download the scenery tile? I won't be able to look > for airports unless I pull the whole world scenery? But some information just doesn't make sense in one huge file that's completely read and parsed every time at startup, then kept in memory. I agree, though, that we have to be careful about it. > Under the current scheme anyone and everyone can scan apt.dat for > every/any airport using common *nix tools like grep or sed. This scheme > breaks that ability. I didn't assume that we are going to drop that single DB with all important info. Just the parts that you don't usually care about, like parking positions, taxiway information or thresholds for VHHH when your are flying in KSFO. > I'll shut up now since I've already been told I'm not a "real" > FlightGear developer and I'm not welcome to create scenery. I hope that wasn't me. I don't label people "real" or "non-real" something. But it's true that sometimes the opinion of people who will do the actual coding as well counts more than that of mere lurkers, especially when there are no arguments, just the usual "we should do this and that". And I don't think you ever belonged to that group. m. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
