Hallo Herr Wilhelm Spiegl via Freedos-devel, am Mittwoch, 22. Mai 2024 um 13:14 schrieben Sie:
> Hi, > thank you for these important informations referring to zoo. > But: A teacher would say: You have missed the point, I have to give you the > worst grade for it. > Reason: The comments will not create a bugfix packet. I am sure that the old > version of zoo will be in FDT2406 too. > OK, then let us keep it. > Sometimes I have the feeling this is intention - or a very strange discussion > culture. > I regret that I have to say this. it seems that no knowledgable person finds zoo interesting enough to fix it. and those who care about zoo have no clue. I regret that I have to say this. Tom > W. Spiegl > > > Sent: Tuesday, May 21, 2024 at 8:21 PM > From: "E. C. Masloch via Freedos-devel" <freedos-devel@lists.sourceforge.net> > To: freedos-devel@lists.sourceforge.net > Cc: "E. C. Masloch" <pus...@ulukai.org> > Subject: Re: [Freedos-devel] zoo > On at 2024-05-19 00:37 +0100, Liam Proven via Freedos-devel wrote: >> On Fri, 17 May 2024 at 17:14, tom ehlert via Freedos-devel >> <freedos-devel@lists.sourceforge.net> wrote: >> >>>> Below 1GB FAT16 uses 8kB clusters. From 1GB-2GB it uses 16kB ones. >>>> (Below ½GB it uses 4kB.) >>> >>> That would require FAT17. >> >> (?) >> >> Not at all. > 64 Ki * 16 KiB = 1024 MiB. (The actual maximum amount of clusters is of > course slightly less than 64 Ki, to be exacting.) So you're off-by-one, > a "2 GB" file system cannot possibly be fully utilised with FAT16 at a > 16 KiB per cluster size. Hence tom's suggestion of FAT17. >> Here is the full list: >> >> FAT12 >> >> Drive size Secs/cluster Cluster size >> < 16 MB 8 4 KiB >> >> FAT16 >> >> Drive size Secs/cluster Cluster size >> < 128 MB 4 2 KiB >> < 256 MB 8 4 KiB >> < 512 MB 16 8 KiB >> < 1 GB 32 16 KiB >> < 2 GB 64 32 KiB > This supports what tom and I wrote: up to (nearly) "2 GB" you need 32 > KiB per cluster. >> < 4 GB 128 64 KiB (Windows NT only) > I agree with this. Enhanced DR-DOS, FreeDOS, and my MS-DOS v4 fork also > support 64 KiB per cluster now. >> < 8 GB 256 128 KiB (Windows NT 4.0 only) >> < 16 GB 512 256 KiB (Windows NT 4.0 only) > EDR-DOS, FreeDOS, and lMS-DOS also support 128 KiB clusters, using 256 > Sectors per Cluster. For further comment see below. >> FAT32 >> >> Drive size Secs/cluster Cluster size >> < 260 MB 1 512 bytes >> < 8 GB 8 4 KiB >> < 16 GB 16 8 KiB >> < 32 GB 32 16 KiB >> < 2 TB 64 32 KiB > It seems that a 2 TiB file system could actually use 8 KiB per cluster > if you were willing to tolerate a FAT size of 1 GiB each. (1 GiB is the > maximum size of a FAT's usable data in FAT32.) > 2 * 1024 * 1024 * 1024 * 1024 / (2 ** 28) = 8192. > Not claiming any formatting tool does this, but the numbers check out. > (If anyone is confused about 2 to the power 28, this is because FAT32 > actually reserves the top 4 bits of every 32-bit FAT entry. They're > masked off by drivers and never set by anyone AFAIK. So the usable > amount of entries is 2 ** 28, not 2 ** 32.) >> Source: >> https://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html >> >> Confirmation: >> https://www.researchgate.net/figure/Default-cluster-size-for-FAT-compatible-OS_tbl1_261851917 > To get to the "Windows NT 4.0 only" entries: I'd never heard of any MSW > supporting 256 Sectors per Cluster. Let alone 512. I didn't find any > other source that confirms this or even explains how such large SpC > values are to be encoded in the file system in order for a driver to use > them. I was also under the impression that EDR-DOS was the first > implementation of FAT FS with 256 SpC. > The only other source I found that supports the possibility of 256 KiB > clusters is in the English Wikipedia page for FAT, in the FAT16B info box: >> Max volume size >> >> 2 GB (with 32 KB clusters) >> 4 GB (with 64 KB clusters) (NT 4, PTS-DOS, EDR-DOS) >> 8 GB (with 128 KB clusters and 1 or 2 KB sectors) (NT 4 and > EDR-DOS only) >> 8 GB (with 128 KB clusters and 512 byte sectors) (EDR-DOS only) >> 16 GB (with 256 KB clusters and 2 or 4 KB sectors) (NT 4 only) > https://en.wikipedia.org/wiki/File_Allocation_Table#Final_FAT16 > You will note that the "8 GB" limits listed use 512 BpS only for the > EDR-DOS 256 SpC extension, only. The other "8 GB" and the "16 GB" > specify larger sector sizes. That would explain how to get to a 256 KiB > cluster, without even the 256 SpC extension. > Regards, > ecm > _______________________________________________ > Freedos-devel mailing list > Freedos-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freedos-devel Mit freundlichen Grüßen / with kind regards Tom Ehlert +49-15151898538 _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
