linux-disks, slices, cylinders, file systems, hard links, symbolic links, du,df

disks, slices, cylinders

Http://blog.chinaunix.net/uid-13245160-id-84370.html

Http://blog.chinaunix.net/uid-17246314-id-5676479.html

Low-level format: The low-level format is to re-empty the contents of the disk, restore the state of the factory, divided the cylinder and track, and then divided into a number of sectors, each sector is divided into the identity of the part ID, Gap and data area of the database.

Partition: File system

Mbr:bootloader (446 bytes), partition table (64 bytes, 4 partitions), end tag

File system: Management software

Block (data block,directory block), Inode, block bitmap, Inode Bitmap, and Super block concept

Http://www.tuicool.com/articles/2yqUZvz

File is block

Directory is also block, store file name and corresponding inode;

Hard links and Symbolic links

Http://blog.chinaunix.net/uid-23208702-id-75180.html

http://blog.csdn.net/hairetz/article/details/4168296/

Hard Links:
1, can only create files, can not be applied to the directory;
2, can not cross the file system;
3, create a hard link will increase the number of times the file is linked;

Symbolic Links:
1, can be applied to the directory;
2, can cross file system;
3, will not increase the number of links linked to the file;
4, the size of the specified path contains the number of characters;

Du: Show file size

Du-s: Displays the entire directory size

[Email protected] ~]# du-hs/etc/
39m/etc/

Du-h
[Email protected] ~]# du-h/etc/
324k/etc/pki/ca-trust/extracted/openssl
184k/etc/pki/ca-trust/extracted/java
620k/etc/pki/ca-trust/extracted/pem
1.2m/etc/pki/ca-trust/extracted
4.0k/etc/pki/ca-trust/source/blacklist
4.0k/etc/pki/ca-trust/source/anchors

DF: Displays the entire disk partition size

[[email protected] ~]# DF
Filesystem 1k-blocks used Available use% mounted on
/dev/sda2 18143556 2659024 14556228 16%/
Tmpfs 953244 953164 1%/DEV/SHM
/DEV/SDA1 289293 32977 240956 13%/boot
/dev/sr0 52770 52770 0 100%/media/cdrom
[Email protected] ~]#

[[email protected] ~]# df-h (HDD size usage)
Filesystem Size used Avail use% mounted on
/dev/sda2 18G 2.6G 14G 16%/
Tmpfs 931M 80K 931M 1%/DEV/SHM
/DEV/SDA1 283M 33M 236M 13%/boot
/dev/sr0 52M 52M 0 100%/media/cdrom

[[email protected] ~]# df-i (inode usage)
Filesystem inodes iused IFree iuse% mounted on
/dev/sda2 1160992 107276 1053716 10%/
TMPFS 238311 5 238306 1%/dev/shm
/DEV/SDA1 76912 76872 1%/boot
/dev/sr0 0 0 0-/media/cdrom
[Email protected] ~]#

[[email protected] ~]# df-p (same line, no wrapping)
Filesystem 1024-blocks used Available capacity mounted on
/dev/sda2 18143556 2659024 14556228 16%/
Tmpfs 953244 953164 1%/DEV/SHM
/DEV/SDA1 289293 32977 240956 13%/boot
/dev/sr0 52770 52770 0 100%/media/cdrom
[Email protected] ~]#

linux-disks, slices, cylinders, file systems, hard links, symbolic links, du,df