Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!apple!rutgers!njin!limonce From: limonce@pilot.njin.net (Tom Limoncelli) Newsgroups: comp.sys.amiga.tech Subject: Re: AmigaDos directory knowledge Message-ID: Date: 28 Nov 89 18:35:55 GMT References: <832@lpami.wimsey.bc.ca> <87.filbo@gorn.santa-cruz.ca.us> Organization: Drew University/NJIN Lines: 34 On my MS-DOS system, my path has about 10 entries. On my Amiga system, my path has about 10 entries. About the same number of files are searched, yet the Amiga does less seeks to the disk. (Diskbuffers flushed, of course). Why is this? Because the Amiga is doing O(N) seeks with hashing; but the MS-DOS does O(N*M/Z) searches. (N = number of directories; M= number of files per directory; Z = number of directory entries per sector) It balances out and the Amiga wins. Also, the Amiga's FFS caches side-sector and directory information better than MS-DOS. I've been told that FFS is modeled after the Berkeley Fast File System and has been benchmarked to be the fastest FS when judged with similar hardware. Why do you think MicroSoft is pushing their "new" high-performance file system for OS/2. There is a LOT of room for improvement over MS-DOS. This has been debated over and over here on comp.sys.amiga. It comes down to this (IMHO); when searching 1 directory for a couple files, sure, MS-DOS FS is a win. But when you are dealing with lots of files, FFS is the winner. Remember, a bubble sort can be faster than a QuickSort if you have a very small number of items. A bubble sort re-written in tight-coded assembler is still O(N^2) and is still a bubble sort. [ Insert favorite computer scientist vs. engineer joke here :-) ] -Tom -- Tom Limoncelli -- limonce@pilot.njin.net -- tlimonce@drunivac.bitnet rutgers!njin!tlimonce -- Drew University, Madison, NJ -- 201-408-5389