NTFS file system


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NTFS file system

  1. 1. NTFS FILE SYSTEM ASSIGNMENT #2 Ravi Yasas Jayasundara ICT 2010 / 2011 / 013
  2. 2. P a g e 1 | 9 Introduction In a windows platform there are many disk file systems. Since they create their operating system, they have introduced many file systems with growing performances. There I have mentioned file systems they have used. I. FAT (File Allocation Table) II. HPFS (High Performance File System) III. NTFS (New Technology File System) IV. ExFAT (Extended File Allocation Table) V. ReFS (Resilient File System) In this project I am going to find out about NTFS. History of NTFS This file system was introduced by Microsoft in 1993 begging with Windows NT 3.1 operating system. Later this is used in windows 2000, Windows XP, Windows 7, and Windows 8 and also in windows server 2003, Windows server 2008 and Windows server 2012. In the 1980s, IBM and Microsoft, we established a joint venture to create the next generation of graphical operating systems. As a result of this project, which is located in OS / 2, do not agree with a number of important issues, IBM and Microsoft are finally separated. OS / 2 is a project of IBM. Microsoft has launched (citation needed) to run on Windows NT. The HPFS file system for OS / 2, which contains several important new features. When you create a new operating system, Microsoft is, they borrowed many of the concepts for NTFS. Why Microsoft moved to New Technology File System? Microsoft needed more supported file system to their operating system in 1993 Windows NT. After this operating system they wanted to make high capacity operating systems with large HDD to done anything that customer needed in these days. So they wanted to make new generation file system to achieve this purpose. Then they moved to NTFS file system which is a great file system still using. Since Windows NT was targeting businesses and corporations, the reliability of the data stored on the system became more of a priority that speed as in the case of home computer users. In a corporate environment, if a system fails and data is lost, speed becomes irrelevant. To support recoverability, the new file system, NTFS, provided file system recovery based upon a transaction-processing model as well as an improved write- caching feature.
  3. 3. P a g e 2 | 9 Differences between main file systems NTFS 5 NTFS ExFAT FAT32 Operating systems Windows 2000 Windows XP Windows Vista Windows 7 Windows Server 2003 Windows Server 2008 Windows NT Windows 2000 Windows XP Windows Vista Windows 7 Windows Server 2003 Windows Server 2008 Windows CE 6.0 Windows Vista Windows 7 DOS v7 Windows 98 Windows ME Windows 2000 Windows XP Windows Vista Windows 7 Windows Server 2003 Limitations Max volume size 26 clusters minus 1 cluster 26 clusters minus 1 cluster 128PB 32GB for all OS, 2TB for some OS Max files on volume 4,294,967,295 4,294,967,295 Unlimited 4,194,304 Max file size 264 bytes minus 1kb 244 bytes minus 64kb 16EB 4GB minus 2 bytes Max cluster number 264 clusters minus 1 232 clusters minus 1 4294967295 4177918 Max file name Length Up to 255 Up to 255 Up to 255 Up to 255 File system features Boot sector location First and last sector First and last sector Sectors 0 to 11 copy in 12 to 23 First sector and copy in sector #6 File attributes Standard and custom Standard and custom Standard set Standard set Alternate streams Yes Yes No No compression Yes Yes No No Encryption Yes No No No Object permission Yes Yes Yes No Disk quotas Yes No No No Sparse files Yes No No No Reparse points Yes No No No Volume mount Yes No No No
  4. 4. P a g e 3 | 9 Performance Built in security Yes Yes Yes minimal ACL only No Recoverability Yes Yes Yes if TFAT activated No Performance Low on small volumes high on large Low on small volumes high on large High High on small volumes low on large Disk space economy Max Max Max Average Fault tolerance Max Max Yes if TFAT activated minimal Versions I. V1.0 Windows NT 3.1 II. V1.1 Windows NT 3.5 III. V1.2 Windows NT 3.51 and Windows NT 4.0 IV. V3.0 Windows 2000 V. V3.1 Windows XP VI. V5.0 Windows NTFS structure Formatting a volume with the NTFS file system results in the creation of several system (metadata) files such as $MFT — Master File Table, $Bitmap, $LogFile and others, which contains information about all the files and folders on the NTFS volume. Formatted NFTS volume System filesMaster file tablePartition boot sector File area
  5. 5. P a g e 4 | 9 NTFS boot sector When you format an NTFS volume, the format program allocates the first 16 sectors for the $Boot metadata file. First sector, in fact, is a boot sector with a "bootstrap" code and the following 15 sectors are the boot sector's IPL (initial program loader). To increase file system reliability the very last sector an NTFS partition contains a spare copy of the boot sector. There are two different structures. I. BIOS parameter block II. Volume boot code NTFS Master File Table (MFT) Each file on an NTFS volume is represented by a record in a special file called the master file table (MFT). NTFS reserves the first 16 records of the table for special information. Each file on an NTFS volume is represented by a record in a special file called the master file table (MFT). NTFS reserves the first 16 records of the table for special information. Below you can see the Master File Table Structure.
  6. 6. P a g e 5 | 9 System Files System File File Name MTF Record Master File Table $Mft 0 Master File Table 2 $MftMirr 1 Log File $LogFile 2 Volume $Volume 3 Attribute definitions $AttrDef 4 Root file name index $ 5 Cluster bitmap $BitMap 6 Boot sector $Boot 7 Bad cluster file $BadClus 8 Security file $Secure 9 Upcase table $Upcase 10 NTFS extension file $Extend 11 Quota management file $Quota 24 Object ID file $Objid 25 Reparse point file $Reparse 26 File area This area re served for the user and in this area, all your files to be stored. MTF record for a small file or directory This design is very fast file access. For example, if you have a list of names and addresses of the FAT file system as a file, you can use the file allocation table. FAT directory entries, including File Allocation Table index. If you want to see the file, the file allocation table FAT first states to ensure that this is available. Then, the file is given a separate number for the chain, is the FAT file. You can file as soon as possible, NTFS, see, but to be used as. Only the file as a record, master file table entries contained in the directory. Instead, information, directory, index information is available. There are quite a few of the MFT file record. MFT cannot be included in the directory entry to record the foreign indicator B-tree is a great guide. Standard information File or directory name Date or indexSecurity description
  7. 7. P a g e 6 | 9 File attributes Standard information Includes information such as Timestamp and link count. attribute Displays a list of all the attribute data that do not fit in the MFT record. filename A repeatable attribute for both short filenames. The long file can be up to 255 characters Unicode. The short is 8.3, case-sensitive name for the file. Additional names, or hard links, required by POSIX can be included as additional attributes File name. Security Descriptor Describes who owns the file and who can access it. data Contains data files. NTFS allows multiple attributes for the file data. Each file typically has one unnamed data attribute. A file can have one or more named data attributes, each of which uses a special syntax. object ID A unique volume ID file. Used by the distributed link tracking service. Not everyone has the object identifier files. Stream logged Utility Similar to a data stream, but operations logged in the log file just like NTFS metadata changes NTFS. This is used by EFS. Reparse Used for volume mount points. They are also used by the installable file system (IFS) filter drivers to mark certain files as special to that driver. Root Index Used to implement folders and other indicators. allocation Index Used to implement folders and other indicators. bitmap Used to implement folders and other indicators. volume information Used only in the $ Volume system file. Contains the volume version. volume Name Used only in the $ Volume system file. Contains the volume label. Features of NTFS file system I. Logging II. Transaction – based III. File and folder permission IV. Disk quotas V. Reparse points VI. Sparse file support VII. Compression VIII. Encryption IX. Alternate data streams X. Recoverability
  8. 8. P a g e 7 | 9 Sparse files Clusters that contain all zeros are not written to disk. Other thing is analysis considerations. A deleted sparse file is hard to recovery. If file system metadata is deleted or corrupted, a sparse file might not be recoverable. File compression Files that are compressed on an NTFS volume can be read and written by any Windows-based application without first being decompressed by another program. Decompression happens automatically during the read of the file. The file is compressed again when it is closed or saved. Recoverability The NTFS recovery disk recovery programs running in the volume NTFS rare, allows the user to NTFS volumes using standard recovery techniques to ensure the transaction log. In case of a system error log files, and automatically restore the file system NTFS checkpoint. For more information about how to restore your system to recover the data, and the Emergency Repair Disk (ERD). Encrypting Uses both symmetric key encrypting (DESX) and asymmetric key encryption (RSA). Generates a single file encryption key (FEK) and encrypts file with FEK using DESX. It stores FEK with file. FEK is encrypted with the public key of the user. FEK to decrypt the user's private key. If the policy allow, is also encrypted FEK using the public key of the recovery agent and (Decrypting the private key recovery Agent). Alternate data streams This means data added to a file. It almost impossible to detect with normal file browsing techniques.
  9. 9. P a g e 8 | 9 Advantages of NTFS file system I. Faster access speed – This file system minimizes the number of accesses required to find a file. II. File and folder security – In this NTFS you are allowed to use the files and folders that you specify, or permissions and access levels you can gain access to. Users in a shared folder on the computer and files stored in files, the NTFS file and folder permissions on the files to a network for users to access and apply. In addition, when you use the NTFS file and folder with a combination of shared folder permissions manipulated. III. Boot sector can be backed up IV. Disk quotas can be set V. Can format volumes up to 2TB VI. NTFS file system is used also in Mac OS x and Linux operating systems. Disadvantages of NTFS file system I. This file system is not applicable for MS DOS, Windows 95, and Windows 98. II. It is slow when using small disks. Extra Creating an NTFS file 1. Read volume boot sector to locate MFT. 2. Read first entry in MFT to determine layout of MFT. 3. Allocate an MFT entry for the new file. 4. Initialize MFT entry with $STANDARD_INFORMATION, etc. 5. Check MFT $Bitmap to find free clusters, using best-fit algorithm. 6. Set corresponding $Bitmap bits to 1. 7. Write file content to clusters and update $DATA attribute with starting address of cluster run and run length. 8. Read root directory (MFT entry 5), traverse index, and find dir1. 9. Read $INDEX_ROOT attribute for dir1 and determine where file1.txt should go. 10. Create new index entry; resort index tree. 11. Enter steps in $LogFile (as each step is taken).
  10. 10. P a g e 9 | 9 Conclusion Windows NTFS file system, a strong expansion such Greece previous file systems, FAT (File Allocation Table) file system and HPFS (High Performance File System). NTFS, capacity added therefore, using fault tolerance and redundant data, and file security, Support for mission critical applications used by businesses and organizations data integrity and high performance requirements. Microsoft as a result of efforts file system, such as data security and the security of the space on the disk. References http://www.ntfs.com http://en.wikipedia.org/wiki/NTFS/ http://support.microsoft.com/ http://technet.microsoft.com/ NTFS concepts by Priscilla Oppenheimer