Introduction
The NTFS (New Technology File System) is a system offiles that came with the launch of Windows NT. Its reliability and performance made that would be adopted in the operating systems later Microsoft, such as Windows XP, Windows Vista, Windows 7 and Windows Server 2008. But, what are the main features of the NTFS file system? In this file system differs? In fact, what is NTFS? The answers to these and other questions, you can check the follow.
Before, which is a file system?
It is not possible to write data on a HD, or in any other storage device to maintain the information accessible and organized without a system of files (file system) – essentially, a structure type that indicates how the files should be written and read by the operating system of the computer.
Is the file system that determines how the information can be saved, accessed, copied, changed, named, and even erased. That is, in short, all and any data manipulation in a storage device needs a file system to that these actions are possible. Without a system files, the data stored would be just a bit set without utility.
There are several file systems available, for the various operating systems and the most varied purposes.
Such as NTFS did?
NTFS is a file system widely used in operating systems Microsoft. His first appearance was in the Windows NT, operating system for use on servers whose first version was released in 1993. However, the history of the NTFS begins long before that.
Until that time, Microsoft did not have any operating system able to make front to the Unix and its variations in applications servers. Your the main products were the MS-DOS line and Windows 3.x, essentially operating systems for use in the home or in the office. It was necessary to create something new, able to compete in the market with solutions based on Unix. Was there that was the Windows NT.
There is no point in a new operating system if the your file system is limited. At the time, Microsoft had in hands the FAT file system. This worked reasonably well in household applications, but does not serve to purposes of the new project through a series of restrictions, among them, low fault tolerance, possibility of use of permissions of files and limitations for the work with large volume of data.
To overcome these and other problems, Microsoft decided to use NTFS. However, contrary to what many people think, the company has not developed this file system alone. She used as the basis of the HPFS (High Performance File System), file system had IBM behind it.
At the beginning of the decade of 1980, both the companies have reached an agreement for the development of OS/2, a system operating until then modern, that has stood out for its graphics capability (at that time, it was very common to use operating systems command-line based).
The problem is that, soon, Microsoft and IBM began to diverge in in respect of several points. As a consequence, melting of the partnership. IBM continued playing the design of OS/2, while Microsoft has been taking care of their interests, more precisely, of the project that resulted in Windows NT.However, the company has not abandoned the partnership hands empty: it has led to several concepts of HPFS – the file system of the OS/2 – related to safety, reliability and performance to later implement them in NTFS.
It is also known that NTFS has anything to do with the Files-11, file system of the VMS operating system, which has passed on to Compaq in 1998, a company that was later acquired by HP. When the work on the VMS were in progress, part of the team moved to Microsoft, with emphasis for the software engineer Dave Cutler, one of the names by back NTFS and Windows NT itself.
The main features of NTFS
The concepts applied to NTFS did with Windows NT and later versions of the system were well received by the market. One of these characteristics says respect to the question of “recovery”: in the case of failures, such as the sudden shutdown of computer, NTFS is able to reverse the data to the condition prior to the incident. This is possible, in part, because, during the boot process, the system operating query a log file that records all the transactions and enters into the action identify it pain points. Also in this aspect, the NTFS also supports redundancy of data, that is, replication, as what is done by systems RAID, for example.
Another striking feature of NTFS is its scheme of access permissions. Unix has always been considered a operating system safe by working with the principle that all files need to have varying levels of permissions of use for users. NTFS is also capable of allow the user to set who can and how to access folders or files.
The NTFS is also quite efficient in working with large files and drives bulky, especially when compared to the FAT file system. You will understand the this is why in the following topic.
Dealing with files
On a hard disk, the storage area is divided in tracks. Each track is subdivided into sectors (learn more in this article about HDs), each with 512 bytes, usually. FAT and NTFS are working with sets of sectors, where each one is known with the cluster (or allocation unit). The FAT16, for example, you can have, commonly, clusters of 2 KB, 4 KB, 8 KB, 16 KB, and 32 KB.
Here there is a possible problem: each recorded file uses as many clusters as are needed to cover its size. If, for example, we have a file with 50 KB, it is possible to save it in two clusters of 32 KB each. You must have noticed then that, in this case, a cluster was with space left over. This the area can be allocated to another file, correct? Wrong! Happens that each cluster can only be used by a single file.If you still have space, this will remain empty. This is a of the problems of the FAT file system.
There is still another limitation: FAT16 works with disks or partitions up to 2 GB. This situation only improves with FAT32, which can work with up to 2 TB (terabytes).
The NTFS file system, in turn, may not rely on this type of limitation. For this, we use 64 bits for addresses data, against 16 of the FAT16 and 32 FAT32. This feature, combined with the size of the clusters, determines the maximum volume of data that each NTFS partition can work. With the use of clusters of 64 KB, this limit can reach up to 256 TB. By default, the size of the clusters is defined automatically based on the capacity of storage device during the installation process of the operating system or formatting a partition – going from 512 bytes to 64 KB -and can also be set by the user with specific procedures.
Fault tolerance
For the preservation of the data, the NTFS uses a scheme of journaling this is the log file mentioned previously. Condensed manner, their functioning occurs in the following way: the log records all the actions that take place in the operating system in relation to the files. When a the document is created, a disk space is allocated to it, your permissions are set, and so on. The question is that if, for example, the computer becomes suddenly without power, the space defined for the file can be allocated, but not used. When the operating system it is re-enabled, query the log file to know which procedures have not been executed completely and run the the corresponding action to correct the problem.
To maintain the integrity of the system, basically, three steps are run: check log to check which clusters should be fixed; a new execution of the transactions are marked as complete at the end of the log; reversal of procedures that could not be completed.
Note that, with this, the NTFS may not be able to retrieve the last recorded data before interrupt, but ensures the full functioning of the system operating eliminating errors that can compromise performance or cause even greater problems.
Permissions
NTFS allows the use of permissions in the operating system, that is, it is possible to define how users or groups of users – can access certain files or certain folders. For example, you can allow the user to Arthur Dent have full control of the folder AbbreviationFinder, but only allow the user to Marvin read andrun said content, without the power to change it.
Each user account created on the system (or group) receives a code single called the Security Identifier (SID). Thus, if a user is deleted and, subsequently, the other is created with the same name,you will need to reapply the permissions because the SID this will be different, in spite of the denomination the same.
The Master File Table (MFT)
FAT is the acronym for File Allocation Table,and it receives this name because it works with a table that basically indicates where are the data of each file. The NTFS file system, however, uses a structure called the Master File Table (MFT), which has virtually the same purpose of FAT, but it works differently.
The MFT is a table that records attributes of each file stored. These attributes consist of a series of information, among them: name, last modified date, permissions (the concept explained in the previous topic) and, especially, location in the storage unit.
As you need to save several information virtually all of the files on the disk, the NTFS reserves space for the MFT – MFT Zone -, usually 12.5% of the partition size. Each file can you need at least 1 KB to the registration of their attributes in the MFT, hence the need for a considerable amount of space for this.
Other features of the NTFS
The NTFS file system is endowed with various resources of a complementary nature or definite that enrich their safety features, performance and reliability. The following are some of them.
Encrypting File System (EFS)
This is a feature that came with Windows 2000 and, as the name suggests, it is a reinforcement of security, because it allows the data protection by encryption with the use of the scheme public keys (learn more about this by clicking on the link earlier). The main advantage is that the owner of the protected files can determine which users can access them. This content is encrypted when the user closes it, but shall be immediately ready for use when opened.
Note that the EFS is not fully available in all versions of Windows compatible with NTFS, such as Windows 7 Home Basic, for example. In addition, it is worth mentioning also that not it is possible to use encryption in the content compressed (following topic).
Data compression Another
Another interesting feature of NTFS is its ability to deal with data compression to save disk space. This the compression consists, basically, to take advantage of structures repeated files to reduce their size.
The FAT also has this ability, but in a limited manner, since it is necessary to compress the partition as a whole. In NTFS, it is possible to compression-only folders or certain files.
To compress a folder in Windows 7, for example, just click it with the right mouse button and select Properties. In the window that appears, basque clicking on the button Advanced on the tab General and mark the option Compress contents to save space disk.
Of course, it is also possible to compress an entire partition: click the button right click the drive, select Properties and in the tab General, select the option Compress this drive to save space.
Worth mentioning that the user does not need to bothering to decompress the files when you need to work with them. To access them, the operating system itself is in charge this. In addition, it is recommended to use this feature with in moderation, and just in case you need to avoid possible performance issues.
Disk Quotas
As well as EFS, this is a newer feature and that is not available in all versions of Windows compatible with NTFS. Their function, basically, is to allow the system administrator to set the amount of disk space each user can use. In this way, you can avoid performance issues or the depletion of resources storage of a server, for example.
Versions of NTFS
You already know that NTFS is not, necessarily, a system files new and that, despite this, it is used with success by Microsoft until the days of today. So, nothing more natural, he suffer updates to adapt to the needs most current versions of Windows.
The most widely-known version of Windows NT, Windows NT 4, it was use of the NTFS 1.2. Apparently, there were versions before this: the 1.0, which was used in Windows NT 3.1, and 1.1, applied to Windows NT 3.5. NTFS 1.2 has passed to be called NTFS 4 in allusion to the existence of the number in question in the name “Windows NT 4”, although this version NTFS also has been used in Windows NT 3.51.
Windows NT was a good time in the market, but then it was replaced by the Windows 2000, which also brought the NTFS 5, version with several new features, among them: Reparse Points, files and folders within the file system can have actions associated with them, so that the operations of private these files can be executed; disk quotas; encryption (EFS); support for sparse data, where it is possible to store efficiently large files but that have structures empty.
Revisions of the NTFS 5 have been released for the Windows XP operating systems and Serves 2003. NTFS 6, and their variations have emerged to versions Vista, 7 and Server 2008 Windows.
New versions may arise with the release other editions of Windows.
Ending
Even when NTFS is used? For the launch of Windows Vista, Microsoft was working on a new file system called WinFS, whose main feature would be its ability to work as a relational database, allowing the user to find easily the files you are looking for.
A series of problems meant that the WinFS wasn’t implemented in the Windows Vista, allowing NTFS to keep your “reign”. There are even rumors that the project WinFS has been cancelled.
Microsoft continues working on the development of new versions of your operating systems, but at least until the publication of this article, there was no information about a new file system, indicating that the NTFS have still a long life ahead of them.
