vi, vim
vi is a very strong command line edit software.
vim was the advanced version of vi, adding the support of GUI.
Except vim, emacs is even stronger than vim.
vim + path to use vim
three modes of vi
command mode
default
i : insert text at the cursor
o : insert a new line below the current one
dd : delete the whole row
yy : put the current row's content to the ram(copy the current line)
n+yy: put n rows' content to the ram(copy n lines)
p : paste
u : revoke the last manipulation
r : replace current character
/ : find key wordinsert mode
i
Esc : back to the command modeex mode
:
:w #save
: q #quit
:q! #force to quit
:set number #show the line number
:! system command # execute a system command
:sh #return to the command line and 'ctrl + d' can return to the vim
Basic concept of disc
转速越快，磁盘性能越强。但是，功率发热量都会高。
SATA
- 柱面(cylinder)
立体，多碟片叠加的柱面圈 - 扇区(sector)
中心扩散出来的扇形 - 磁头(head)
读写数据，每个磁盘上下都有个磁头
磁盘在linux中的表示
设备名称一般为hd[a-z]或sd[a-z]，如hda,hdb,sda,sdb
IDE设备的名称为hd[a-z],SATA,SCSI,SAS,USB等设备名称为sd[a-z]
concept of partition
将一个磁盘逻辑的分为几个区，每个区当作独立磁盘，以方便管理。
不同分区用： 设备名称 + 分区号 ，如sda1,sda2
主流的分区机制分为MBR和GPT两种。
MBR
Master Boot Record. Traditional one. Applied to most BIOS PC device.
- support 32bit and 64bit
- there is a limit for partition
- support no more than 2T hard disk.
MBR partition
- main partition
at most 4 - extended partition
take a place of the main partition.
can't be used. still need logical partition. - logical partition
can only be created by creating an extended partition first.
Linux can support at most 63 IDE partition and 15 SCSI partition.
GPT
A new one.
- support more than 2T
- compatible with MBR
- only can be used on the hardware that supports UEFI
- only 64bit
- Mac,Linux both support GPT
- Windows 7 64bit, windowsServer2008(win10,win8?)
