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UNIX File System Layout. boot block contains bootstrap code that is read into the machine to boot the operating system super block describes the state of a file system, how large it is, how many files it can store, where to find free space on the file system, etc - PowerPoint PPT Presentation
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Yukon Chang, Fall 1996 Operating System (II) Chapter 11 Supplement Slide 1
UNIX File System Layout boot block contains bootstrap code that is read into the
machine to boot the operating system super block describes the state of a file system, how lar
ge it is, how many files it can store, where to find free space on the file system, etc
inode list is a list of inodes (explained later) data blocks store file data and administrative data
data blocksinode listsuperblock
bootblock
Yukon Chang, Fall 1996 Operating System (II) Chapter 11 Supplement Slide 2
Inodes (Index Nodes) inodes exist in a statis form on disk, it consists of
• file owner (individual owner and group owner)• file type (regular, directory, character/block device, ...)• access permission (r-xr-x---)• access and last modify time (of file and inode)• number of links to the file• pointers to data blocks• file size
see Fig. 11.7 on the textbook
Yukon Chang, Fall 1996 Operating System (II) Chapter 11 Supplement Slide 3
Directory Block notably missing from inode information is the file name file name is kept in a directory entry of directory block the first two entries in a directory have names . and ..
toinode
5 foo.c 3 bar mumble6
toinode
toinode
unusedspace
Yukon Chang, Fall 1996 Operating System (II) Chapter 11 Supplement Slide 4
Hard Links an inode can be linked from many different directory e
ntries, i.e., it may have many names
toinode
5 foo.c 3 bar mumble6
inode2714 reference count = 2
Yukon Chang, Fall 1996 Operating System (II) Chapter 11 Supplement Slide 5
Symbolic (Soft) Links a symbolic link is a special file that contains a
pathname.
directories
/usr/joe
/usr/sue
foo
bar
inodesfile
content
/usr/joe/foo
Hello, world