Interesting... What information is tored in the "FAT refered table" it needs 32 bits?
Alain Imre Leber escreveu: > Here are the numbers for the data structures used by defrag, when calculated > for FAT32. > > Cluster movable map: 32 MB (fat size * 1 bit) > FAT refered map: 32MB (fat size * 1 bit) > FAT refered table: 1024MB (fat size * 4 byte) > Dir refered table (take 100000 files): (# files * 6 bytes) 0,5 MB > > total: 1088,5 MB (and I though XMS only went to 64MB) > > In depth: > > Cluster movable map: indicates which clusters are movable. > FAT refered map: indicates which clusters are refered to in the FAT > FAT refered table: stores the back pointers for the FAT clusters > DIR refered table: stores the back pointers for the directory refered clusters > > Imre > >> ----- Oorspronkelijk bericht ----- >> Van: Eric Auer [mailto:[EMAIL PROTECTED] >> Verzonden: dinsdag, maart 18, 2008 10:22 PM >> Aan: freedos-devel@lists.sourceforge.net >> Onderwerp: Re: [Freedos-devel] Fwd: freedos defrag methods (OT) >> >> >> Hi! >> >>> For this it is very sad that FreeDOS does not use the LEAN file system >>> (http://freedos-32.sourceforge.net/doc/lean.html) instead. That has back >>> pointers for pretty much everything and would as a consequence be much >>> faster. >> A lean ad ;-). But you can just as well build data structures with the >> back pointers in RAM while defrag and similar tools are running. Takes >> roughly the same amount of RAM as the metadata (FAT, dir) takes on >> disk. As you often copy those to RAM for work like defragging to get >> fast access, you basically get some overhead for making the pointers >> plus you double the amount of RAM that defrag consumes ;-). >> >> Note that for example DOSFSCK takes several times the size of your FAT >> plus several times the size of all directory entries of RAM, too. >> Actually this would be interesting to know more about: Could some of >> you run DOSFSCK 2.11c with the -v option on large filesystems, with >> many files and/or many clusters, and report how much heap it tells >> you that it has used? It is displayed when DOSFSCK is done. Seems to >> be 5..10 times the FAT size for systems with few files here... Some >> "bad case of FAT16" would be interesting (might use 1-5 MB maybe?) >> as well as, of course, typical FAT32 filesystems. You can find >> DOSFSCK version 2.11c on my page, as usual: >> www.coli.uni-saarland.de/~eric/stuff/soft/by-others/dosdosfsck-2.11c.zip >> (you should already have cwsdpmi anyway, otherwise see e.g. my page) >> >> Eric >> ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
