Newsgroups: comp.unix.wizards Path: utzoo!henry From: henry@utzoo.uucp (Henry Spencer) Subject: Re: System V file systems Message-ID: <1988Oct27.173247.2789@utzoo.uucp> Organization: U of Toronto Zoology References: <6413@daver.UUCP> <8332@alice.UUCP> Date: Thu, 27 Oct 88 17:32:47 GMT In article hedrick@geneva.rutgers.edu (Charles Hedrick) writes: >(2) System V (at least SVr2, and I think also SVr3) uses a free list, >which it does not keep in order, so an active file system fragments >very soon. The BSD file system is designed to avoid fragmentation. >Of course this problem will not show if you do your tests right after >creating the file system. Or if you run your tests in a time-sharing environment, where the disk heads are always on their way to somewhere else anyway. If you read the fine print, all the Berkeley performance tests were run single-user!! We conjectured a long time ago that the only feature of the 4.2 filesystem that matters much in a timesharing environment is the big block size; I haven't yet seen any solid results (numbers, not anecdotes) that would contradict this. -- The dream *IS* alive... | Henry Spencer at U of Toronto Zoology but not at NASA. |uunet!attcan!utzoo!henry henry@zoo.toronto.edu