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Performance FAT and NTFS

This article assesses the performance of file systems used in operating systems Windows95/98/ME and WindowsNT/2000. Article does not contain schedules and test results, as these results are too heavily dependent on the case, testing methods and specific systems, and have little connection with reality. In this paper describes the overall trends and considerations related to the performance of file systems. After reading the material, you get information for reflection and will be able to draw conclusions, to understand what system will be faster in your circumstances, and why. Perhaps some facts can help you to optimize the performance of their vehicles in terms of file systems, catch any decisions that will increase the speed of the entire computer. The review mentions three-FAT system (the FAT16), FAT32 and NTFS, as the main issue before the Windows2000 users is a choice between these options. I send apologies to users of other file systems, but the problem of choosing between the two, apparently quite equivalent, options acutely now only available for Windows2000. I hope, however, expressed concerns that strike you as curious, and you will be able to come to some conclusions and the system with which you are working. This article consists of many parts, each of which focuses on a single issue of speed. Many of the sections in a field are closely intertwined. Nevertheless, it does not transform the art of gruel, in the appropriate section, I will only write about that is relevant to the discussion at the moment so, and nothing more. If you have not found any important facts in the text-not hurry to wonder : most likely you will meet them later. You also do not make any hasty conclusions about the disadvantages and advantages of a system, as well as the contradictions and pitfalls of these considerations very, very much. In the end, I will try to collect everything that can be said about the performance of the system in real-world conditions. 1. The theory most fundamental properties of a file system, affecting the performance of disk-structure of the organization and storage of information that is how, indeed, turned himself filesystem. The first section is an attempt analysis of this aspect of work, that is physical work with the data structures and file system. Theoretical considerations, in principle, could miss those who are interested only in the practical aspects of performance file systems can apply immediately to the second part of the article. To begin, I would like to note that any file system in one way or another store files. Access to data files is a major and integral part of the file system, and therefore, you must first say a word about it. Any file system stores data files-some of the sectors that are being used equipment and the driver, as the smallest unit of useful information drive. The sector in the vast majority of today's systems is 512 bytes, and all file systems to read the information and pass it without any processing applications. Were there any exceptions? Virtually none. If the file is stored in compressed or encrypted form as possible, for example, NTFS, then, of course, the restoration or interpretation of information and resources spent time processor. In other cases, reading and writing of data file is the same speed, what file system you are used to. See the fundamental processes of the system to access files : Search data file to determine the areas in which the disk is kept a bit of the file, a process which is fundamentally different expression in different file systems. Keep in mind that this is only seeking information on the location of the file-access to the data, fragmented or not, there is no longer seen as the process the same for all systems. These are the "extra " activities to be carried out before the system access to real data files. At that affect this option : to speed navigation file (arbitrarily block access to the file). Any work with large data files and documents if their size, and more than a few megabytes. This parameter shows how much file system itself suffers from the fragmentation of files. * NTFS can provide quick search fragments, since all the information is stored in several very compact entries (typical size of a few kilobytes). If the file is highly fragmented (contains many fragments), NTFS have to use a lot, which often lead to store them in different locations. The extra traffic heads in search of the data, in this case, lead to a severe slowdown in the process of finding data on the location of the file. * FAT32, because of the large area of the table itself will be crippled if the file fragments scattered all over the disk. In fact, that the FAT (file Allocation Table, file Allocation Table) is a mini-disk image, which includes each cluster. To access a piece of the file system FAT16 and FAT32 had to be a part of the FAT. If the file, for example, is in three pieces-at the beginning of the drive in mid - and late-in the FAT system, we will have to turn to a bit of FAT in its beginning, middle and end. In FAT16 system, where the maximum size of the FAT is 128 KB, it is no problem, the whole area FAT simply stored in memory or read from disk in a single pass and buffered. FAT32, on the other hand, is typical of hundreds of kilobytes of FAT, and the big drive even a few megabytes. If the file is located in different parts of the drive system is forced to perform hard disk head movement as many times as groups of fragments in different areas is file, which is very, very slow process of finding fragments of a file. Conclusion : The absolute leader, FAT16, it will not make the system to make extra disc operation for the purpose. Then comes NTFS, the system also does not require reading unnecessary information, at least so far, is a reasonable number of file fragments. FAT32 hard until reading extra hundreds of kilobytes of FAT, if the file dispersed to different areas of the disk. Working with the impressive size of the files on FAT32, in any case, is hard to understand where on the disk is a fragment of a file is to be reviewed the sequence clusters file from the beginning, treat for every one cluster (every 4 MB file in a typical system). It is noteworthy that when the file is fragmented, but is compact heap of debris-FAT32 is not experiencing great difficulties, as well as physical access to the area FAT will also compact and buferizovan. Search space This operation is in the event that the file be created from scratch or copied to disk. Find a place in the physical data file depends on how information is stored on the disk of employees. At that affect this option : to speed the creation of the files, especially large ones. Saving or in real time large multimedia files (. Wav, for example), copy large amounts of information, etc. This parameter shows how quickly to find a place to record new data on the disk and what operations it will have to do so. * To ascertain whether the cluster is free or not, based on the FAT system should see a record FAT, with this cluster. The size of a FAT16 record is 16 bits, the same record FAT32-32 bits. To find the disk space may be required to view almost the entire FAT is 128 MB (maximum) for FAT16 and to a few megabytes (!) In FAT32. In order not to make the search space of a catastrophe (for FAT32), the operating system has to go to various ruses. * NTFS is a bitmap free, one cluster with one bit. To find the disk space is measured in tens of times smaller than the FAT and FAT32 system. Conclusion : NTFS is the most efficient system of free space. It is noteworthy that the act "head on" with FAT16 or FAT32 very slowly, so in order to find space in these systems use different methods of optimization, and as a result, there is an acceptable speed. (What is certain-the search space when working in DOS to FAT32-catastrophic to speed the process, because no optimization is not possible without the support of at least as serious operating system). Working with directories and files, each file system is the basic operation of the file-access, deleting, creating, moving, etc. The speed of these operations depends on the principles of data storage on a single file and directory structure of the device. At that affect this option : the speed of any dealings with the file, including the speed of any operation of the file, especially in places with a large number of files (thousands). * FAT16 and FAT32 are very compact directories size of each record which very small. Moreover, because of past historical storage long file names (more than 11 characters), the FAT file system is not very efficient and seemingly failed, but very economical structure of these very long file names. Using FAT directory is fast enough, as the vast majority of cases folder (directory data file) and is not fragmented disk in one place. The only problem, which could significantly reduce the rate at which catalog FAT-many files in a single directory (about a thousand or more). Storage area network-linear array is not able to effectively search files in a directory, and to find the file must handle large amounts of data (an average of half a file folder). * NTFS uses a much more effective way of addressing - binary tree, the principle of which can be found in another article (NTFS file System). The organization provides work effectively with directories of any size-NTFS directories nor increase in the number of files in one directory and to the tens of thousands. It should be noted, however, that the directory NTFS is much less tightly structured than FAT directory is linked to the much larger (several times) as a record catalogue. This fact leads to what directories to NTFS that in the vast majority of cases highly fragmented. The size of a typical directory of e FAT- fit in one cluster, while hundreds of files (or even less) in the directory to NTFS already led to the size of the file directory, exceeding the typical size of one cluster. This, in turn, almost guarantees fragmentation file directory, which, unfortunately, are often negated the benefits of a much more effective organization of the data. Conclusion : a directory structure on the theory NTFS much better, but the amount of inventory in the hundreds of files is almost irrelevant. Fragmentation NTFS directories, but confidence is already at this level directory. For small and medium-sized directories NTFS, as this is not sad is, in practice, less speed. Advantages NTFS directories are real and true only if one catalog has thousands of files-in this case, speed up fragmentation of the catalogue and difficulties with the physical handling of data (for the first time further cache directory). Hard work with directories containing thousands of files and more, is literally on NTFS is several times faster, and sometimes gains in speed compared to FAT and FAT32 dozens of times. 2. Practice Unfortunately, as is often the case in all kinds of computer issues, the practice is not well with theory. NTFS with the seemingly obvious advantages in the show was less exciting results, as might be expected. What other considerations affect the performance file system? Each of the issues discussed further contributes to the final performance. Keep in mind, however, that actual performance is the result of all the factors at once, it is in this part of the article should not jump to hasty conclusions. 2.1. The amount of memory (cache) Too many of today's file systems or buferiziruyutsya cached in the computer's memory, thus avoiding unnecessary physical operations reading data from disk. For the normal (high) of the system must be kept in the cache following types of information : data on the physical location of all open files. This is, after all, would turn to the system files and libraries, access to which is literally constantly, without reading performance (not related to the files themselves), information from the disk. The same applies to those files, which are executed at the time - that is, to perform modules (. exe and. dll) of active processes in the system. This category also includes the files, which are the work of (primarily inventory and virtual memory, different. Ini files, and document files and applications). * The most frequently used folders. These include desktop, menu, "Flight", system catalogs, directories, Internet cache, and so forth. * Data on free disk space, or the information that will find a place to keep new data on the disk. If that base of information is not available directly from RAM, the system will have to perform many unnecessary operations even before it starts working with real data. Are these amounts in different file systems? Or, the issue in more practical terms, how much free RAM you need to have in order to effectively work with a file system? * FAT16 is very little data on those responsible for the file system. Of the office area can be identified himself only area FAT, which may not exceed 128 MB (!) - This area is responsible for search and fragments of files, and search for free space volume. Catalogues FAT system is also very compact. The total memory required for an efficient work with FAT happened, can range from hundreds of kilobytes to megabayta- another subject of great size and the number of directories that are working. * FAT32 different from FAT16, but it is an area FAT may have larger sizes. At volumes of 5 to 10 GB of FAT hold of a few megabytes, and this is a very sizeable, reliable cache that is not possible. Nevertheless, state FAT, but rather the fragments, which are responsible for the location of the working files, in the vast majority of systems are in memory of the machine - is spent on the order of several megabytes of RAM. * NTFS, unfortunately, has a much greater memory requirements necessary for the operation of the system. First, caching very difficult large directories. Size alone directories, which are actively working system can routinely reach several tens of megabytes or even megabytes! Add to this the need to cache the card free volumes (hundreds of MB) and MFT records of the files, with which the business (in a typical system-on 1 KB per file). Fortunately, NTFS is a good system for storing data, which do not result in any increase in the flat areas with increased disk. The amount of data that the system operates on the basis of NTFS, little dependent on the volume and substantive contribution to the volume of data to be cached, making catalogs. Nevertheless, this is quite sufficient to only the minimum amount of data required for basic caching of NTFS, got to 5 - 8 MB. Unfortunately, we can say with confidence : NTFS lose huge amounts of their theoretical performance to a lack of caching. On systems with less than 64 MB of memory, NTFS can not be quickly FAT16 or FAT32. The only exception to this rule-FAT32 disks with dozens of GB (I would personally seriously feared FAT32 disks of over, say, 30 GB). In other cases, a system with less than 64 megabits of memory just to work with FAT32 faster. Typical is the memory of 64 MB, unfortunately, also not possible to effectively work with NTFS. Small and medium-sized disk (up to 10 GB) in the typical FAT32 system will work, perhaps a bit faster. The only thing that could be said about the performance of systems with RAM-system working with FAT32, will be much stronger suffer from fragmentation, as the system NTFS. But even if occasionally hard drives, the FAT32, in terms of performance, is the preferred option. Many people, however, opt for such a system NTFS, simply because of the fact that it gives some very important benefits, while a typical performance loss is not very high. Systems with more than 64 megabytes, and especially with 128 megabytes or more of memory, can confidently cache is all that is necessary for systems, and it is on such computers NTFS is likely to show higher performance because of improved data organization. 2.2. Performance Drive Do physical hard disk parameters on the performance of the file system? Yes, but not much, but affected. These are the parameters of the physical disk, which can have a different impact on different kinds of file systems : * Time random access (random seek time). Unfortunately, access to the system on a typical drive for more complex file system (NTFS) have to perform, on average, more heads of the disk than in a simple system (FAT16 and FAT32). A far greater fragmentation directories to the fragmentation of the system make it NTFS drives much more susceptible to arbitrary speeds (accidental) on the disk. For this reason, use of slow NTFS (old) drive is not recommended as a high (worst) search paths is another plus for the FAT system. * A Bus Mastering. Bus Mastering-special treatment of the driver and controller, the use of which exchange with CD made without the participation of the processor. It is noteworthy that the late caching NTFS can operate much more efficiently when there Bus Mastering, because NTFS is a pending record much more data. Without Bus Mastering System now meet infrequently (usually drives or controllers working in the mode or PIO3 PIO4), and if you are working with such a disk is the most likely NTFS lose a couple of points performance, especially when dealing modifying directory (for example, Intensive work on the Internet, work with the Internet cache). * Caching as read and write at the level of hard disks (HDD of a buffer from 128 KB to 1-2 MB in modern expensive disk), a factor that will be more useful system based on FAT. NTFS for reasons of reliability data storage system is a modification of the flag "no cache entry, so NTFS weak performance depends on the ability of the caching HDD. FAT systems, in contrast, will receive some of the cache plus entries at the physical level. It should be noted that, generally speaking, seriously take into account buffer size HDD in evaluating the performance of different file systems is not. Summarizing the impact of speed and disk controller to speed the system as a whole, one can say this : NTFS suffers from a slow drive much stronger than FAT. 2.4. Cluster I would like to say a word on the size of the cluster-parameter which file systems FAT32 and NTFS formatting can be set almost at random. First, it must be said that most cluster size is almost always a great performance. Cluster of NTFS volume, but have less impact on performance than the cluster size to the FAT32 system. * A typical cluster size for NTFS-4 KB. It is noteworthy that with the increased size of the cluster off built into the file system to compress individual files, as well as standard API stop working hard, or the overwhelming number defragmentatorov, including built-in Windows 2000 will be unable to defragment the drive. SpeedDisk, however, it can work without the use of the API. The best in terms of speed, at least for the medium and large files, it (the Microsoft) 16 MB size. Increase the size of further unwise because of spending too much on inefficient data storage and by the tiny further increase performance. If you want to improve performance at the cost of loss of NTFS compression-think about formatting disk cluster size, large than 4 KB. But keep in mind that this will be a modest increase in speed, which often is not even reduce the effectiveness of files on the disk. * Performance FAT32 system, in contrast, can be significantly improved by increasing cluster size. If NTFS little effect on the size and nature of the system area, the FAT system, increasing cluster in half, we cut FAT area in the same twice. Recall that in a typical system, FAT32 is very important for the performance area is a few megabytes. Reduction of FAT several times a marked increase in performance will, as the volume of system data file system-much shorter and less time spent reading data on the location of files and the amount of RAM necessary to buferizirovaniya this information. Typical of cluster systems FAT32 is also 4 KB, and increase it to 8 or even 16 MB, especially for large (ten or more gigabytes) of disk-a reasonable step. 2.3. Other considerations NTFS is a complex system, so, unlike FAT16 and FAT32, there are other factors that can lead to a significant slowdown of NTFS : * Disk NTFS received conversion section FAT16 or FAT32 (team convert). The procedure in most cases is a difficult case for performance, as well as the structure of the office of NTFS is likely to get very fragmented. If possible, avoid converting other systems in NTFS, as this would create a very bad drive, which will not even typical disk (the non), a type Diskeeper- or built into Windows 2000. * Intensive work with the disk, filled more than 80% - 90%, is a catastrophic event for the performance NTFS, as well as the fragmentation of files and, most importantly, the field office will be fantastic to grow rapidly. If your disk is used in such a mode-FAT32 is a good choice under any other circumstances. 3. Conclusions In this final part of "one line" collected key performance features of these three file systems. FAT-pros : * To work requires little memory. * Quick work with small and medium-sized directories. * Disk commits an average of fewer head movements (compared with NTFS). * Effective at the slow disk. FAT-minuses : * catastrophic loss of performance with increasing fragmentation, especially for large disks (only FAT32). * Difficulties with random access to a large (say, 10% or more of disk size) files. * Very slow work with the directory containing many files. NTFS-pros : * file fragmentation had little effect on the file system itself, the work has only a fragmented system in terms of access to the data files. * The complexity of the directory structure and the number of files in one directory to neither special performance constraints. * Quick access to arbitrary piece of a file (such as editing large. wav files). * Very fast access to small files (several hundred bytes), the entire file in the same location, and system data (MFT record). NTFS-minuses : * Substantial demands on system memory (64 MB-absolute minimum, preferably more). * The slow drives and controllers without Bus Mastering severely reduces performance NTFS. * Job Directory-sized by the fact that they almost always fragmented. * Disk, long employed in a full 80% to 90%, will be to show very poor performance. I would like to emphasize once again that, in practice, the major factor affecting the performance of the file system is, strangely enough, the memory machine. Systems with 64-96 MB of memory-a point at which performance NTFS and FAT32 roughly equivalent. Note also the complexity of the data on your machine. If you do not use anything but the simplest applications and the operating system - it may happen that FAT32 will show higher performance and the machine with a large number of memory. NTFS system, which assumed for the future, and this is the real future for the majority of today has, unfortunately, it may not come. At this point NTFS ensures stable and indifferent to a number of factors, but perhaps still low by typical "game" home-performance system. The main advantage of NTFS in terms of speed is that the system insensitive parameters such as directories complexity (the number of files in a directory), the amount of disk fragmentation, etc. In the FAT system, on the other hand, each of these factors lead to a substantial reduction in the speed of work. Only highly complex systems, such as graphic stations, or simply to serious office computers with thousands of documents, or even worse, for file servers, the advantages of NTFS will be real gains speed, which is sometimes visible to the naked eye. Users who do not have big drives slaughtered information, and not using complex programs do not expect miracles from NTFS speed, in terms of performance on simple home of a much better show FAT32.
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