Hi
Wanted to cover file systems
NTFS, ext3 , ext4,XFS .How to do and details
a file can be video audio file
it can be formated text
most opersation system has folder directories
drive lettes
how is data writen into storage media is the
thing that operating system manages
EXT2,EXT3 ,NTFS , FAT, HPFS
role of OS is to define API for file access and
the structure (directories names)
OS also provides drivers for physical access
file is a name for group of data.This group of
data
also has attribute like owners, permissions
date/times etc
structure of file can be explicit or implicit
like .exe it executible file and .txt is text
file can have access type like direct sequential
etc
file can have performance caching , organization
,memory management
file system also has directories management like
hierarchical form.
some file system can be across multipl physical
drives
like linux allows you to mount a drive so that
the directory sturcure remains the same
not always structure is hierarchical .like
mainframes the data is separated by using
abc.kkk.aaa.kklkl
reference paths ..
how data is saved on disk
. the OS always know where the root directory is
so its always saved on some posistion
so OS can decide where to start from
so how space is allocated .. usually a fixed
allocation of blocks , there is a directory that
contains a list of blocks for a file
OS access method masks use of non contiguos block
this is called fragmentaion
see how data is saved on ms block
file name 8 ext 3 attribut 1 reserved 10 time2
date 2 1st block 1 and size 4
FAT file allocation table -- the location of
first block will be kept in file allocation table
in windows 98.. the same structure FAT-32 this
was because of larger disks
base 8 ext3 attribute 1 ,NT 1,Sec 1 , creation
3,last accessed 2 , starting block 2 , last write
4 starting block 15.31 , file size 4
in unix i node number2 file name 14
Wanted to cover file systems
NTFS, ext3 , ext4,XFS .How to do and details
a file can be video audio file
it can be formated text
most opersation system has folder directories
drive lettes
how is data writen into storage media is the
thing that operating system manages
EXT2,EXT3 ,NTFS , FAT, HPFS
role of OS is to define API for file access and
the structure (directories names)
OS also provides drivers for physical access
file is a name for group of data.This group of
data
also has attribute like owners, permissions
date/times etc
structure of file can be explicit or implicit
like .exe it executible file and .txt is text
file can have access type like direct sequential
etc
file can have performance caching , organization
,memory management
file system also has directories management like
hierarchical form.
some file system can be across multipl physical
drives
like linux allows you to mount a drive so that
the directory sturcure remains the same
not always structure is hierarchical .like
mainframes the data is separated by using
abc.kkk.aaa.kklkl
reference paths ..
how data is saved on disk
. the OS always know where the root directory is
so its always saved on some posistion
so OS can decide where to start from
so how space is allocated .. usually a fixed
allocation of blocks , there is a directory that
contains a list of blocks for a file
OS access method masks use of non contiguos block
this is called fragmentaion
see how data is saved on ms block
file name 8 ext 3 attribut 1 reserved 10 time2
date 2 1st block 1 and size 4
FAT file allocation table -- the location of
first block will be kept in file allocation table
in windows 98.. the same structure FAT-32 this
was because of larger disks
base 8 ext3 attribute 1 ,NT 1,Sec 1 , creation
3,last accessed 2 , starting block 2 , last write
4 starting block 15.31 , file size 4
in unix i node number2 file name 14
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