Messages in this thread |  | | From | "Randal, Phil" <> | Subject | RE: kernel patch support large fat partitions | Date | Fri, 4 Jan 2002 10:40:49 -0000 |
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It is now up to Version 1.03
http://www.microsoft.com/hwdev/hardware/fatgen.asp
Phil
--------------------------------------------- Phil Randal Network Engineer Herefordshire Council Hereford, UK
> -----Original Message----- > From: CJ [mailto:cj@cjcj.com] > Sent: 04 January 2002 02:49 > To: Vijay Kumar > Cc: Alan.Cox@linux.org; linux-kernel@vger.kernel.org > Subject: Re: kernel patch support large fat partitions > > > FAT32 stores 28 bit cluster numbers. You need to increase > cluster size > instead of the 28 bits to stay FAT32. The spec is > fatgen102.pdf:, I'll > mail it to you. > > Hardware White Paper Hardware White Paper > FAT: General Overview of On-Disk Format > Version 1.02, May 5, 1999 > Microsoft Corporation > > Vijay Kumar wrote: > > > Alan, > > > > This is regarding a change I had to make to the kernel 2.2.17-14 to > > support really large drives. In our project we deal with > huge drives, > > sometimes drives larger than 128GB. The file system is > FAT32 and only > > one partition is create on any drive. During our testing we > realized > > that linux fat implementation doesn't support partitions > larger than > > 128GB(actually 64GB because of a bug in fat implementation). > > > > This limitation is imposed by the data structures used by the linux > > fat implementation to read/write directory entries. A > 'long' data type > > is used to access directory entries on the disk, of which > only 28 bits > > are used to identify the sector that contains the directory > entry and > > the rest 4 bits are used to specify offset of the directory entry > > inside the sector. Using 28 bits to identify a sector means > we cannot > > access sectors beyond 128GB (2^28*512), thus limiting us > from creating > > partitions larger than 128GB on large disk drives. > > > > I have made changes to fat, vfat and msdos file system > implementations > > in the kernel to use larger data types, thus allowing us to create > > larger partitions. As per the GPL I would like to make the patch > > available to everyone and also in case somebody has run > into the same > > problem(who cares about fat in the linux world). The patch has been > > fairly well tested only on our systems(p3, 700MHz with FC). I truly > > appreciate if you & anybody in the kernel mailing list have any > > feedback about the changes. > > > > The patch is applicable to only 2.2.17-14 kernel and may require > > changes to use with other kernel versions. As far as I know none of > > the kernel versions provide any fix for this problem. > > > > Thanks, > > - Vijay > > > > - > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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