fdisk

Command action
   a   toggle a bootable flag
   b   edit bsd disklabel
   c   toggle the dos compatibility flag
   d   delete a partition #清空分区表
   l   list known partition types
   m   print this menu
   n   add a new partition
   o   create a new empty DOS partition table #创建新的dos 分区表
   p   print the partition table  #打印出分区表
   q   quit without saving changes
   s   create a new empty Sun disklabel
   t   change a partition's system id
   u   change display/entry units
   v   verify the partition table
   w   write table to disk and exit
   x   extra functionality (experts only)

fidsk --- p

Command (m for help): p

Disk /dev/sda: 1198.0 GB, 1197998080000 bytes #disk name 磁盘大小
255 heads, 63 sectors/track, 145648 cylinders  #磁头，扇区，磁道
Units = cylinders of 16065 * 512 = 8225280 bytes #每个容量扇区大小为512字节，6065=255*63 因为每一个磁头都是在同一个柱面的，63表示每个磁道上的扇区数量，这两个数的乘积表示一个柱面上的扇区数量；所以16065*512表示一个柱面的大小是8225280字节
Sector size (logical/physical): 512 bytes / 512 bytes# 表示一个扇区的大小是512字节
I/O size (minimum/optimal): 262144 bytes / 524288 bytes 
Disk identifier: 0x000ed559

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          26      204800   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              26        4203    33554432   82  Linux swap / Solaris
/dev/sda3            4203      145649  1136159744   83  Linux

参考：
磁盘磁头，扇面信息介绍：https://segmentfault.com/a/1190000007392163