When You Format A Drive, You Must Choose The Size Of Which Of The Following File System Attributes?

Maximum File Size

Computer-Assisted Attacks and Crimes

In The Official CHFI Study Guide (Exam 312-49), 2007

Investigating Code Injection Attacks

Evidence of a code injection attack is rarely institute in the Web server logs. If the Web designer writes failed input information to a log file, you lot will probably encounter the diverse attempts to go the set on right. If at that place are no logs of wrong attempts to fill out a form or other inputs, you may have to resort to network traffic sniffer logs.

Using an open source tool such every bit Wireshark to capture traffic going to the server and then searching for either all requests going to the input folio or field names on the folio may requite you a good accounting of the malicious traffic and the IP address of the source.

You may take to gather some rather large files to catch i of the attempts. Past setting the capture filter on the sniffer of your pick to just the traffic going to the server you can reduce the capture file considerably.

In Wireshark the capture filter would be dst host xxx.xxx.xxx.xxx (the x'south are the IP address of the server). Notation that yous should test to encounter how big this file gets over the space of an hour or two and make sure you have sufficient storage space for the resulting file earlier you get out the sniffer running unattended for long periods.

Head of the Class…

Wireshark File Sizes

The creators of Wireshark and its predecessor, Ethereal, knew that files tin can get large in a hurry, so they have a few helpful items in the Capture dialog box. Yous tin set limits to file sizes in several different ways.

Yous can fix the maximum file size to a specific number of bytes, kilobytes, or megabytes.

You tin can set up the maximum number of minutes or hours that the capture runs.

Y'all can set the files to suspension into smaller chunks then that they fit on a CD or DVD easily.

Knowing these options and using them as you lot see fit during traffic capture sessions tin can mean the difference betwixt having all the information you need for an investigation and exposing yourself to some serious headaches.

For more helpful hints on Wireshark, see the wiki at http://wiki.wireshark.org.

If you lot know that one of the input fields on a page you are investigating is labeled homePhone, you can utilise the frame contains display filter frame contains "homePhone". Whatsoever packets that take information going to the input field will be shown and can be examined for proper or malicious content.

Other locations of evidence may exist establish in access logs or transaction data. Don't forget to look at transaction times also. If you are seeing a large number of transactions in a short period, or at odd hours, you lot may exist seeing signs of an attack.

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Managing Users

Tony Redmond , in Microsoft Exchange Server 2007 with SP1, 2008

8.5.6 Logging Managed Binder activeness

By default, Exchange 2007 does not log whatsoever details of the work performed by the Managed Folder Assistant. If you want to gain some insight into what happens when the Managed Folder Assistant runs, you tin can enable logging on a mailbox server with the Set-MailboxServer command. For case:

Later you enable logging, Substitution generates daily log files in the \Programme Files\Microsoft\Exchange Server\Logging\Managed Folder Banana directory. Similar to the parameters available to command message tracking logs, you can modify how Exchange manages these log files.

In this command, we prepare a number of parameters.

▪: The full size limit for the directory that stores the managed folder banana log files is set up to 100MB. After Exchange reaches this limit, it deletes the oldest log files to brand room.
▪: The historic period limit for log files is fix to 30 days. Exchange deletes log files that are older than the limit.
▪: The maximum file size for a managed folder assistant log is ready to 25MB (the default is 10MB). Later the log file reaches the specified size, Exchange creates a new log. Note that the 10MB default limit is more than sufficient for the vast majority of servers.
▪: The location where Exchange creates log files for the Managed Folder Assistant is moved away from the default on the system disk. It is best practise to move all log files generated past Exchange off the arrangement disk.
▪: Exchange is instructed to log information nigh letters that take reached their memory limit.
▪: Exchange is instructed to log the subject for whatsoever bulletin that is processed by the Managed Folder Assistant.

Figure viii-38 illustrates some case content extracted from a managed folder assistant log. Three actions are highlighted:

one.: The Managed Folder Banana has candy an detail that is by its memory date.
2.: The Managed Binder Assistant has journaled an particular in a managed folder.
3.: The Managed Folder Banana is processing a mailbox to employ a managed folder policy.

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Maintaining Difficult Disks

In How to Cheat at Windows Organisation Administration Using Command Line Scripts, 2006

Supported File Systems

Windows XP and Windows Server 2003 support the following types of file systems:

▪: FAT file organization The File Allocation Table (Fat) file system is the original file system used past MS-DOS and other Windows operating systems. Information technology is a data construction Windows creates when a volume is formatted. This structure stores information about each file and directory so that it can be located later on. The maximum disk sectionalisation size is 4 GB. On floppy disks, this is limited by the chapters of the disk. The maximum supported file size on hard disks is 2 GB.
▪: FAT32 file arrangement FAT32 stands for File Allocation Table32, an advanced version of the FAT file system. The FAT32 file arrangement supports smaller cluster sizes and larger volumes than the FAT file organization, which results in more efficient space allocation. FAT32 file systems back up a maximum partition size of 32 GB for Windows XP and Windows Server 2003. The maximum size file size is 4 GB.
▪: NTFS NTFS, which stands for New Engineering science File System, is an avant-garde file system that provides operation, security, reliability, and advanced features not establish in FAT and FAT32 file systems. Some of the features of NTFS include guaranteed volume consistency by means of transaction logging and recovery techniques. NTFS uses log file and checkpoint information to restore the consistency of the file arrangement. Other advanced features of NTFS include file and folder permissions, pinch, encryption, and disk quotas. You lot cannot use NTFS on floppy disks due to its limited chapters (Sysinternals has a utility for using NTFS on floppy disks. For more data check out Syngress Publishing's Winternals Defragmentation, Recovery, and Administration Field Guide, ISBN one-59749-079-2). The maximum supported partitioning size ranges from ii TB to 16 TB. The maximum file size can be up to 16 TB minus sixteen KB. The minimum and maximum partition sizes vary past the partition manner called when the operating system was installed.

Formatting a Disk or Partition with the Format Command

A hard disk or a sectionalization is of no employ to any operating arrangement unless it is formatted. You use the Format command to format raw disks or deejay partitions with a selected file organisation. You can utilise the FAT, FAT32, or NTFS file arrangement when formatting a disk with Windows XP and Windows Server 2003 operating systems. When a disk is formatted, all data on the deejay is lost, only the Format command displays a warning message before information technology starts. After the disk is formatted, a new root directory and the specified file system are created on the disk. The syntax of this command is:

Table v.1 explains the parameters of this command.

Table 5.1. Parameters of the Format Command

Parameter	Description
Volume:	Specifies the drive, volume, or mounted volume that you wish to format. The bulldoze letter is followed by a colon (:).
/fs.FileSystem	Specifies the file system to apply for formatting. This parameter supports the Fatty, FAT32, and NTFS file systems. When you are using this control for floppy disks, you lot can use but the Fatty file system.
/v.Characterization	Used to assign a label to the formatted volume. If you practise not use it, or if you utilize it without specifying the label, the Format command prompts you to specify a label once the formatting is complete.
/q	Used to perform a quick format of a previously formatted volume. Information technology causes the command to delete the existing root directory and file table and cuts the fourth dimension required to format a disk when you are sure that it does not take any bad sectors.
/a.UnitSize	Used to specify the allocation unit size for disk clusters.
/c	Used only with NTFS file systems. It automatically compresses all files created on the new volume.
/ten	Used to dismount the mounted volume (if required) during the formatting process.
/f:Size	Used for floppy disks to specify their size. Accustomed parameters include one,440, one,440 1000, 1,440 KB, 1.44, 1.44 Grand, and 1.44 MB. It is preferred over the /t:Tracks and /due north:Sectors parameters.
/t:Tracks /n:Sectors	Used together to specify the number of tracks (/t:Tracks) and sectors per track (/n:Sectors) on the deejay. Microsoft recommends that yous use the /f:Size parameter instead of using these 2 parameters together. When you utilise /f:Size to define the size of the deejay, you cannot employ the /t:Tracks or /n:Sectors parameter.

Allocation Unit Size

You tin can specify the size of the resource allotment unit of measurement with the Format command by using the /a:UnitSize parameter. Each hard disk is made upwardly of minor units known as sectors or clusters. The resource allotment unit size defines the number of bytes per cluster on the formatted deejay. The following is a list of the supported resource allotment unit sizes for the Fatty, FAT32, and NTFS file systems:

▪: 512 Sets the unit size to 512 bytes per cluster.
▪: 1024 Sets the unit size to 1,024 bytes per cluster.
▪: 2048 Sets the unit size to ii,048 bytes per cluster.
▪: 4096 Sets the unit size to 4,096 bytes per cluster.
▪: 8192 Sets the unit size to 8,192 bytes per cluster.
▪: 16K Sets the unit size to sixteen kilobytes (16 KB) per cluster.
▪: 32K Sets the unit size to 32 kilobytes (32 KB) per cluster.
▪: 64K Sets the unit of measurement size to 64 kilobytes (64 KB) per cluster.

When yous do not utilize the /a:UnitSize parameter with the Format control, the system chooses an appropriate unit size based on the size of the volume.

Master Craftsman …

Cluster Size and Number of Clusters

The advantage of using smaller sizes for disk clusters when formatting a disk or a partition is the cosmos of small placeholders for files on the disk. Smaller cluster sizes are very useful in situations where you lot demand to store a large number of pocket-sized files on a disk with limited storage capacity. This helps reduce wasted space on small-scale disks when y'all are creating clusters of sizes as large as 64 KB. Another limitation of big cluster size on NTFS partitions is that you cannot utilise NTFS compression if the cluster si2e is larger than 4,096 bytes (or four KB).

The number of clusters is also limited in Fatty and FAT32 volumes. With FAT volumes you can have a maximum of 65,526 clusters and with FAT32 volumes yous tin can have between 65,527 and 4,177,917 clusters.

WARNING

The following section contains some examples of the Format command. Do not use this control on any production computer because it volition delete all data on the disk or division yous specify. Even when yous are trying this control on a test figurer, make sure that you dorsum upward all data outset.

Examples of the Format Control

The post-obit are some examples of the Format command:

The first command formats the floppy disk in the computer's A: drive with all default settings. The second control formats the floppy disk and assigns it the Backup label. When you practice not apply the /v:label parameter or do not specify a book label with the /v parameter, the post-obit message is displayed after the floppy disk is formatted:

You lot tin can enter a label for the floppy disk or press the Enter key if you lot practise not want to utilize one. Since a floppy drive is formatted in the given instance, and floppy disks back up only the Fatty file system, the number of characters y'all tin can include in the label is limited to 11. Here are two more than examples:

The first command performs a quick format of the East: drive with the NTFS file organisation. The second command formats the F: drive with the FAT32 file organisation and an allotment unit of measurement size of 512 bytes. Before the control starts formatting a partition on the difficult disk, it displays the following alert bulletin:

This is your chance to abolish the Format command, if y'all have used it by mistake or selected a wrong partition to format. Printing the Y central if you want to proceed with the format or press the Due north central to arrest the command. During the format process, the command displays its progress as a percentage of the total disk space formatted. When formatting is complete the Format command displays the total disk infinite and the available disk infinite in kilobytes (KB).

If you want the newly formatted volume to compress all files stored in information technology, you can utilize the /c parameter. This feature is available on NTFS volumes simply. Hither is an example:

After the volume is formatted, all files created on the Eastward: book will be automatically compressed.

Note

You cannot utilise the Format command over the network to format a disk on a remote computer. Even on a local computer you must take administrative rights to utilize the Format control.

Get out Codes for the Format Command

The Format command comes with its ain set up of leave codes that indicate the success or failure of the control, and the reason for failure. When you utilise the Format command in a batch file, you tin control the process by using the exit codes it generates. Leave codes are normally used equally arguments with the Errorlevel parameter in if and goto statements for conditional processing of batch file commands. Table 5.two lists the exit codes for the Format command.

Tabular array 5.two. Exit Codes for the Format Command

Get out Code	Description
0	The format process completed successfully without errors.
one	Incorrect parameters were supplied with the Format control.
4	A fatal error occurred during the format procedure. This may be any error other than errors 1, 4, and 5.
5	The user pressed the N key to cease the format process when prompted with the question, "Proceed with Format (Y/N)?"

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Assay of Operating Organization Components

Paul J. Fortier , Howard E. Michel , in Computer Systems Performance Evaluation and Prediction, 2003

xiii.2.ii Windows XP architecture

Windows XP Professional person is built on the proven lawmaking base of Windows NT and Windows 2000, which features a 32-fleck computing compages, also as a fully protected retentivity model. Windows XP Professional is designed to allow multiple applications to run simultaneously, while ensuring cracking system response and stability.

Disk management

Microsoft Windows XP offers two types of disk storage: basic and dynamic.

Basic disk storage

A deejay initialized for bones storage is called a bones disk. A bones disk contains basic volumes, such as principal partitions, extended partitions, and logical drives. Additionally, bones volumes include multidisk volumes, which are created by using Windows NT 4.0 or earlier, such as book sets, stripe sets, mirror sets, and stripe sets with parity. Windows XP does not support this multidisk bones book.

Dynamic disk storage

A deejay initialized for dynamic storage is called a dynamic disk. A dynamic disk contains dynamic volumes, such as simple volumes, spanned volumes, striped volumes, mirrored volumes, and RAID-5 volumes. With dynamic storage, deejay and volume management can be performed without the need to restart Windows. Mirrored volumes or RAID-v volumes cannot be created on Windows XP Professional-based computers. Notwithstanding, a Windows XP Professional person-based calculator can be used to create a mirrored or RAID-5 book on remote computers that are running Windows 2000 Server, Windows 2000 Advanced Server, or Windows 2000 Data Centre Server.

Storage types are split from the file organisation blazon. A basic or dynamic disk can comprise any combination of FAT16, FAT32, or NTFS partitions or volumes.

File systems

Windows XP supports three unlike file systems: File Allocation Tabular array (Fatty); FAT16, FAT32, and NTFS (NT file system); NTFS is the recommended file system. NTFS provides advanced file arrangement features such equally security, transacted operations, big volumes, and better performance on large volumes. Such capabilities are not available on either FAT16 or FAT32. Windows XP provides native support for NTFS volumes on such big sizes, while a FAT32 volume is supported only for sizes up to 32 GB. Under Windows XP, NTFS supports a maximum file size of upward to the disk size. Windows XP delivers new features (such as support for acquiring and editing video files) that frequently event in cosmos of files that exceed four GB in size. NTFS is a journaling file system. NTFS writes a log of changes being made, which offers pregnant benefit in cases where a organization loses power, experiences an unexpected reset, or crashes. NTFS tin apace return the disk to a consistent state without running CHKDSK. This yields a better user experience and results in fewer back up calls.

Memory management

Windows XP, like most modern operating systems, uses virtual retention. Windows XP regularly checks that the memory assigned to a particular application is really in employ and maintains an estimate for each application indicating the amount of retention that could reasonably be taken away without affecting functioning. A reserve of retention is kept on hand to exist used as needed. When this reserve sinks likewise depression, it is replenished by trimming working sets. These estimates are used as a guideline to determine where retentivity should be taken from.

Virtual memory is divided amid the space taken by the applications, driver code, allocated and mapped data used past the system, and the space used by the organization. In Windows, concrete memory has page-pooled and non-folio-pooled allocations. Non-folio-pooled retention is for code that is time critical, such every bit the Virtual Retentiveness Manager (VMM). Page-pooled retentiveness is mapped to deejay files and allows the Bone to swap the memory pages out to disk if additional physical memory is needed elsewhere. Pool memory is managed by a organization of descriptors, called page table entries (PTE), that incorporates retention page frame numbers which point to concrete memory pages. In addition to memory page frame numbers, the PTE contains bits on the use status of the page—in use, dirty, clean, and unused. The memory manager keeps rails of page status with page table lists for fetching and reuse.

In the fight between drivers or processes for retention under low-retentiveness conditions, the user often loses. Mostly, these weather are temporary and are relieved when a driver or procedure frees up its blocks. When a driver or application process needs retentiveness, it asks the organization for a memory allocation. The resource allotment is either provided or denied. In past versions of Windows, resource allotment routines that must succeed were allowed to force the organization to give the driver some memory. Unfortunately, during lean memory times, it could crash the system. To help get past these low times, Windows XP no longer permits drivers to allocate must-succeed requests. If an awarding or driver uses a must-succeed request, information technology is denied. All internal Windows XP drivers have been rewritten to avoid the use of must-succeed requests. Third-political party drivers will also have to comply to earn signed driver status.

Some other stride taken past Windows XP for more robust memory handling is I/O throttling. For operation reasons, Windows tries to do as much processing in parallel as possible. However, if memory utilise gets to the point where there is none left to allocate, Windows will throttle down its processing of retentiveness to one page a time, using the resources it can. While this slows the organization, it doesn't crash.

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Deject Data Storage

Dan C. Marinescu , in Cloud Computing (Second Edition), 2018

half dozen.4 General Parallel File System

One time the distributed file systems became ubiquitous, the natural adjacent stride in the file systems evolution was supporting parallel access. Parallel file systems permit multiple clients to read and write concurrently from the same file. Support for parallel I/O is essential for the performance of many applications [334]. Early supercomputers such as the Intel Paragon took advantage of parallel file systems to support data-intensive applications.

Concurrency command is a critical effect for parallel file systems. Several semantics for handling shared and concurrent file access are possible. One choice is to have a shared file arrow. In this instance successive reads issued past dissimilar clients advance the file pointer. Another semantics is to permit each client to have its own file pointer.

The General Parallel File Organisation (GPFS) [444] was developed by IBM in early 2000s every bit a successor of the TigerShark multimedia file system [226]. GPFS is a parallel file system emulating closely the beliefs of a general-purpose POSIX system running on a single system. GPFS was designed for optimal functioning of large clusters. GPFS can back up a file system of up to four petabytes consisting of upwardly to $4 096$ disks of 1 TB each, run into Figure 6.6 . The maximum file size is $2^{63} - one$ bytes.

A file consists of blocks of equal size, ranging from 16 KB to 1 MB stripped across several disks. The system could support non only very big files, but also a very large number of files. GPFS directories employ the extensible hashing techniques to access a file. A hash function is practical to the name of the file; then the n depression-order bits of the hash value give the cake number of the directory where the file data can be found, with due north a office of the number of files in the directory. Extensible hashing is used to add together a new directory block. The organisation maintains user data, file metadata, such as the time when concluding modified, and file organisation metadata, such every bit allocation maps. Metadata, such as file attributes and data block addresses, is stored in inodes and in indirect blocks.

Reliability is a major concern in a organisation with many physical components. To recover from system failures GPFS records all metadata updates in a write-alee log file. Write-ahead means that updates are written to persistent storage only after the log records take been written. For example, when a new file is created, a directory bloc must exist updated and an inode for the file must be created. These records are transferred from cache to disk after the log records have been written. When the organisation ends upwardly in an inconsistent state, the directory bloc is written and and then if the I/O node fails earlier writing the inode, the log file allows the organization to recreate the inode record. The log files are maintained by each I/O node for each file system it mounts and any I/O node is able to initiate recovery on behalf of a failed node. Disk parallelism is used to reduce the access time; multiple I/O read requests are issued in parallel and data is pre-fetched in a buffer pool.

Data striping allows concurrent admission and improves performance, but tin have unpleasant side-effects. Indeed, when a single disk fails, a big number of files are afflicted. To reduce the impact of such undesirable events, the system attempts to mask a single disk failure or the failure of the access path to a deejay. The system uses RAID devices with the stripes equal to the block size and dual-attached RAID controllers. To farther ameliorate the fault tolerance of the organisation GPFS data files, also as metadata, are replicated on ii different physical disks.

Consistency and operation, critical for whatever distributed file system, are difficult to balance. Support for concurrent access improves performance, only faces serious challenges for maintaining consistency. GPFS consistency and synchronization are ensured by a distributed locking mechanism. A central lock manager grants lock tokens to local lock managers running in each I/O node. Lock tokens are also used by the cache management arrangement.

Lock granularity has of import implications on the functioning of a file arrangement and GPFS uses a multifariousness of techniques for different types of data. Byte-range tokens are used for read and write operations to data files every bit follows: the first node attempting to write to a file acquires a token roofing the entire file, $[0, \infty]$ . This node is allowed to carry out all reads and writes to the file without any need for permission until a second node attempts to write to the aforementioned file; then, the range of the token given to the outset node is restricted. More precisely, if the kickoff node writes sequentially at offset $f p_{one}$ and the second ane at get-go $f p_{2} > f p_{1}$ , then the range of the tokens for the 2 tokens are $[0, f p_{2}]$ and $[f p_{2}, \infty]$ , respectively, and the two nodes can operate concurrently without the need for further negotiations. Byte-range tokens are rounded to block boundaries.

Byte-range token negotiations among nodes employ the required range and the desired range for the showtime and for the length of the current and the future operations, respectively. The information-shipping, an alternative to byte-range locking, allows fine-grain information sharing. In this mode the file blocks are controlled by the I/O nodes in a circular-robin manner. A node forrard a read or write operation to the node controlling the target cake, the only ane allowed to access the file.

A token manager maintains the land of all tokens; information technology creates and distributes tokens, collects tokens one time a file is closed, downgrades/upgrades tokens when boosted nodes request admission to a file. Token management protocols attempt to reduce the load place on the token manager; for example, when a node wants to revoke a token information technology sends messages to all the other nodes property the token and forwards the respond to the token manager.

Access to metadata is synchronized; for example, when multiple nodes write to the same file, the file size and the modification dates are updated using a shared write lock to access an inode. One of the nodes assumes the part of a metanode and all updates are channeled through information technology; the file size and the last update time are determined by the metanode after merging the private requests. The same strategy is used for updates of the indirect blocks. GPFS global data such as ACLs (Access Control Lists), quotas, and configuration data are updated using the distributed locking mechanism.

GPFS uses disk maps for the direction of the disk infinite. The GPFS block size can be every bit large as ane MB and a typical block size is 256 KB. A block is divided into 32 sub-blocks to reduce disk fragmentation for pocket-size files thus, the block map has 32 bits to indicate if a sub-bloc is gratis or used. The arrangement disk map is partitioned into n regions and each deejay map region is stored on a different I/O node; this strategy reduces the conflicts and allows multiple nodes to allocate disk infinite at the same time. An allocation manager running on 1 of the I/O nodes is responsible for actions involving multiple disk map regions. For instance, it updates free space statistics, helps with deallocation by sending periodically hints of the regions used by private nodes.

A detailed discussion of system utilities and of the lessons learned from the deployment of the file system at several installations in 2002 tin can be found in [444]; the documentation of the GPFS is available from [247].

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Video Direction Systems

Vlado Damjanovski , in CCTV (3rd Edition), 2014

The unlike file systems

Each different operating system uses some kind of file arrangement in order to write data on hard drives and removable media, then that afterward on the user is able to find it and read it. Inherently, this is a fundamental and of import concept that defines the flexibility, chapters, and security of various systems. This is why we will mention the most common ones here.

All file systems consist of structures necessary for storing and managing data. These structures typically include an operating system boot record, directories, and files.

A file system performs three main functions: it tracks the allocated and unused space; it maintains directories and filenames; and it tracks the concrete coordinates where each file is stored on the disk.

Dissimilar file systems are used by dissimilar operating systems. Some operating systems (such as Windows) can recognize only some of its own file systems, while others (such as Linux and Mac OSX) can recognize several, including file systems from another Bone.

I important example of this interchangeability is the USB keys, or flash-disks, every bit they are sometimes called. Typically, a USB storage device is formatted with Microsoft's FAT32, but it tin be read by well-nigh all Bone. But, the FAT32 comes with its own limitations, such equally the maximum file size in one block, or the maximum chapters information technology can accost. This may eventually touch some exporting capability from some machines, so installers and integrators should exist aware of such limits.

It is also important to mention that some manufacturers use raw data writing on hard disks without formatting them. This allows for quick installation of new drives when the old ones neglect, as it does not crave fourth dimension-consuming formatting. Other manufacturers accept their ain formatting method where video data is written sequentially, thus making the USB storage device quicker in searching and playback.

Some of the virtually mutual file systems in utilize today are:

Ext/ext2/Ext3/Ext4 – Extended file organization, designed for Linux systems

FAT – Used on DOS and Microsoft Windows, working with 12 and 16 $.25

FAT32 – Fat with 32 bits

HFS/HFS + – Hierarchical File System, used on Mac Os systems

HPFS – High Performance File organization, used on IBM's Os/2

ISO 9660 – Used on CD and DVD-ROM disks on a variety of platforms

GPFS – IBM Journaling File system, provided in Linux, Windows and AIX

NTFS – Used on Windows NT-based systems (Windows 2000, XP, 7)

ReiserFS/iv – File system that uses journaling, used in Linux and Unix

FATX – Used in Microsoft's X-Box

LTFS – IBM's file system for Linux, Mac OSX and planned for Microsoft Windows

ReFS – Microsoft's new 2012 Server file system

Later in this chapter nosotros are going to address the about common file systems in CCTV workstations, servers, DVRs, and NVRs more than in-depth.

FAT (File Allocation Table)

Introduced by Microsoft in 1983, the File Allocation Tabular array (FAT) is a file system that was developed for MS-DOS and used in consumer versions of Microsoft Windows upwards to and including Windows ME. Even with 512-byte clusters, this could give up to 32 MB of space – enough for the 10 MB or 20 MB XT hard drives that were typical at the fourth dimension. As hard drives larger than 32 MB were released, large cluster sizes were used. The employ of 8192-byte clusters allowed for file organization sizes up to 512 MB. Even so, this increased the problem of internal fragmentation where small-scale files could consequence in a not bad deal of wasted space; for example, a 1-byte file stored in a 8192-byte cluster results in 8191-bytes of wasted space.

The Fatty file organisation is considered relatively uncomplicated, and because of that, it is a popular format for floppy disks. Moreover, it is supported by virtually all existing operating systems for personal computers, and because of that it is often used to share information between several operating systems booting on the same computer (a multi-boot surround). Information technology is also used on solid-country retentivity sticks and other similar devices.

The FAT file system also uses a root directory. This directory has a maximum allowable number of entries and must be located at a specific place on the disk or segmentation.

Although it is one of the oldest file formats, FAT is probable to remain in use for a long fourth dimension because it is an ideal file system for pocket-sized drives. It is too used on other removable storage for noncomputer devices, such as flash retentiveness cards for digital cameras, USB flash drives, and the like.

FAT32 (File Allocation Table 32-bit)

In 1997, Microsoft created FAT32 as an extension to the FAT concept because the cluster growth possibility was exhausted. The FAT32 was an enhancement of the Fat file system and was based on 32-bit file allotment table entries, rather than the sixteen-bit entries used by the previous Fat organization. As a consequence, FAT32 supports much larger disk or partition sizes (up to two TB). This file system can be used past Windows 95 SP2 and Windows 98/2000/XP. Previous versions of DOS or Windows cannot recognize FAT32 and are thus unable to kick from or use files on a FAT32 disk or sectionalisation. The FAT32 file system uses smaller clusters than the Fatty file system, has duplicate kick records, and features a root directory that can be of whatever size and tin can be located anywhere on the deejay or partitioning. The maximum possible size for a file on a FAT32 volume is iv GB. Video applications, large databases, and some other software hands exceed this limit which is the reason some DVRs/NVRs exporting to USB keys intermission upwards the files to such sizes.

The FAT32 cluster values are represented by 32-chip numbers, of which 28 bits are used to hold the cluster number. The kick sector uses a 32-bit field for the sector count, limiting the FAT32 volume size to 2 TB for a sector size of 512 bytes and 16 TB for a sector size of 4,096 bytes. FAT32 was introduced with Windows 95 in 1996, although reformatting was needed to apply information technology, and DriveSpace 3 (the version that came with Windows 95 OSR2 and Windows 98) never supported it. Windows 98 introduced a utility to catechumen existing hard disks from FAT16 to FAT32 without loss of information. In the Windows NT line, native support for FAT32 arrived in Windows 2000. In theory, this should back up a total of approximately 268,435,438 clusters, assuasive for bulldoze sizes in the multi-terabyte range. However, due to limitations in Microsoft'south ScanDisk utility, the Fatty is not allowed to grow across 4,177,920 clusters, placing the book limit at 124.55 GB. The open Fatty + specification proposes how to store larger files upwards to 256 GB on slightly modified and otherwise backwards compatible FAT32 volumes, only imposes a run a risk that disk tools or FAT32 implementations not aware of this extension may truncate or delete files exceeding the normal FAT32 file size limit.

NTFS (New Technology File System)

NTFS or New Technology File Arrangement is the standard file system of Microsoft Windows NT and its descendants, Windows 2000, Windows XP, Windows vii and Windows Servers. NTFS is a descendant of HPFS, the file system designed by Microsoft and IBM for Bone/2 as a replacement for the older FAT file system of MS-DOS. The improvements over FAT was support for meta-data and the use of advanced data structures in order to improve performance, reliability, and disk infinite utilization. NTFS incorporates these plus additional extensions such as security admission control lists and file system journaling. In NTFS everything that has anything to do with a file (name, cosmos date, admission permissions, and even contents) is written down as meta-data. Internally, NTFS uses binary trees in club to store the file organization data; although complex to implement, this allows fast admission times and decreases fragmentation. A file system journal is used in gild to guarantee the integrity of the file system itself (just non of each individual file). Systems using NTFS are known to have improved reliability, a specially important requirement considering the unstable nature of the older versions of Windows NT.

NTFS has gone through an evolution of versions, starting from five.one.0 in mid-1993 with Windows NT 3.1, then 5.1.one in 1994 for NT three.5, then v.ane.2 for NT4 in 1996 (some times referred to as NTFS 4.0), v.three.0 for Windows 2000 in yr 2000 (some times referred to as NTFS 5.0), upward to 5.three.1 for Windows XP in 2001 (some times referred to every bit NTFS v.one).

The primal system construction of the NTFS file system is the master file table (MFT). NTFS keeps multiple copies of the critical portion of the MFT to protect confronting corruption and data loss. Like Fatty and FAT32, NTFS uses clusters to store data files. However, the size of the clusters is not dependent on the size of the disk or partition. A cluster size as small as 512 bytes can be specified, regardless of whether a sectionalization is half dozen GB or 60 GB. Using pocket-size clusters not simply reduces the amount of wasted disk space, but also reduces file fragmentation, a condition where files are cleaved up over many not-contiguous clusters, resulting in slower file access. Because of its ability to use small-scale clusters, NTFS provides skillful operation on large drives. Finally, the NTFS file arrangement supports hot fixing, a process through which bad sectors are automatically detected and marked so that they will not exist used.

In theory, the maximum NTFS volume size is ii⁶⁴− 1 clusters. However, the maximum NTFS volume size equally implemented in Windows XP Professional is 2³²− 1 clusters partly due to partition table limitations. For example, using 64 kB clusters, the maximum Windows XP NTFS volume size is 256 TBs. Using the default cluster size of 4 kB, the maximum NTFS book size is 16 TB. Because segmentation tables on primary kicking record (MBR) disks simply support partition sizes up to ii TB, dynamic volumes must be used to create NTFS volumes over 2 TB. As designed, the maximum NTFS file size is 16 EB (sixteen × 1024⁶ or 2⁶⁴ bytes). As implemented, the maximum NTFS file size is 16 TB. With Windows viii, the maximum NTFS file size is 256 TB.

Ext2/iii/4

The ext2 or 2nd extended file system was the standard file system used on the Linux operating system for a number of years and remains in wide utilise. It was initially designed by Remy Card based on concepts from the extended file arrangement. It is quite fast, enough so that it is used every bit the standard against which to measure many benchmarks. Its chief drawback is that it is not a journaling file system. The Ext2 file system supports a maximum disk or division size of 4 terabytes. Its successor, Ext3, has a journal and is compatible with Ext2.

The ext3 or third extended file system is a journaled file arrangement that is coming into increasing use among users of the Linux operating organization. Although its operation and scalability are less attractive than those of many of its competitors such as ReiserFS and XFS, it does have the significant reward that users can upgrade from the popular Ext2 file system without having to back up and restore data. The ext3 file system adds a periodical without which the file system is a valid Ext2 file organization. An Ext3 file system can be mounted and used equally an Ext2 file system. All of the file system maintenance utilities for maintaining and repairing the Ext2 file system tin can also be used with the Ext3 file arrangement, which means Ext3 has a much more mature and well-tested set of maintenance utilities bachelor than its rivals.

The ext4 is the fourth extended, journaling, file system for Linux, adult every bit the successor to ext3. The journal allows the file system to quickly return to a consistent state later an unscheduled organization shutdown caused past a ability outage or a system crash. This feature greatly reduces the risk of file system abuse (and the demand for lengthy file system checks). ReiserFS also handles directories containing huge numbers of small files very efficiently. Unfortunately, converting a organization to ReiserFS requires users of Ext2 to completely reformat their disks, which is a disadvantage not shared by its main competitor Ext3. Considering of its advantages many Linux distributions have made information technology the default file system.

The ext4 file arrangement can support volumes with sizes up to one Exabyte (EB) (i,000 Terabytes = 10¹⁸ Bytes) and files with sizes up to 16 Terabytes (TB). Ext4 is backward compatible with ext3 and ext2, making it possible to mount ext3 and ext2 as ext4. Ext3 is partially forward compatible with ext4.

Ext4 does not even so have every bit much support equally ext2 and ext3 on not-Linux operating systems.

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