On 4 June 2011 21:50, Timothy Murphy <gayleard@xxxxxxxxxx> wrote: [Partition does not end on cylinder boundary] > Does this matter? > If so, what can you do about it? > I get it after partitioning with fdisk, > choosing partitions of size 50GB, etc. The message refers to an attempt to describe the end sector using an assumed/fictional number of cylinders, heads, sectors/track. Probably there are not enough bits in the CHS fields to accomodate a disk of the size you are using. Linux uses LBA and does not care about CHS. Some bootloaders require correct CHS values but only to locate the start, not the end. """ There is no known operating system that requires this restriction. However, there exists software that tries to guess the disk geometry by looking at the CHS start and end values in a partition table. Note that with large disks CHS values are entirely meaningless. """[1] """ In a DOS type partition table the starting offset and the size of each partition is stored in two ways: as an absolute number of sectors (given in 32 bits) and as a Cylinders/Heads/Sectors triple (given in 10+8+6 bits). The former is OK - with 512-byte sectors this will work up to 2 TB. The latter has two different problems. First of all, these C/H/S fields can be filled only when the number of heads and the number of sectors per track are known. Secondly, even if we know what these numbers should be, the 24 bits that are available do not suffice. DOS uses C/H/S only, Windows uses both, Linux never uses C/H/S. If possible, fdisk will obtain the disk geometry automatically. This is not necessarily the physical disk geometry (indeed, modern disks do not really have anything like a physical geometry, certainly not something that can be described in simplistic Cylinders/Heads/Sectors form), but is the disk geometry that MS-DOS uses for the partition table. Usually all goes well by default, and there are no problems if Linux is the only system on the disk. However, if the disk has to be shared with other operating systems, it is often a good idea to let an fdisk from another operating system make at least one partition. When Linux boots it looks at the partition table, and tries to deduce what (fake) geometry is required for good cooperation with other systems. """[2] [1] http://www.win.tue.nl/~aeb/partitions/partition_types-2.html [2] man fdisk -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
