Re: impact of 4k sector size on the IO & FS stack

[Douglas Gilbert <dougg@torque.net>]

Bryan Henderson wrote:
>> DOS partitions start partitions on odd-numbered sectors
> 
> I don't get this.  If you mean partitions defined by the classic DOS 
> partition table format, then AFAICS, such a partition can start in any 
> sector.

Bryan,
Typically the first partition on a DOS partitioned disk
starts at the next available sector after the mbr
which, for some bizarre reason, is 63 sectors long.
Hence:

# fdisk -lu /dev/hda

Disk /dev/hda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors
Units = sectors of 1 * 512 = 512 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *          63    18314099     9157018+   c  W95 FAT32 (LBA)
/dev/hda2        18314100    19551104      618502+  82  Linux swap / Solaris
/dev/hda4        19551105   156296384    68372640   83  Linux


> 
>> so presuming you have odd-aligned disks, life is good.
> 
> What is an odd-aligned disk?

s/disk/partition/ ?
Perhaps hda1 and hda4 above are examples.

Doug Gilbert