file system

5.5.3 File System Facts

This lesson covers the following topics:

File system components

Formatting

NTFS

Extended File Allocation Table (exFAT)

File System Components

A file system organizes and stores data and information on a storage device. The file system and the operating system work together to ensure data availability, integrity, and accessibility. The following table describes the four main components of a file system.

Component Description

Partition A partition is a logical division of a storage device (e.g. a hard disk drive or solid-state drive). Before a drive can be partitioned, it must first be initialized. During this process, a partition style is selected, such as Master Boot Record (MBR) or GUID Partition Table (GPT). A single storage device can contain one or more partitions.

A partition can be initially created without being formatted, but in most cases it is formatted to allow an operating system to be installed or to store data. When a partition is formatted, it is given a drive letter to help a user distinguish which partition is being used, such as C:\ or D:\. A partition cannot span to a separate physical storage device.

Reasons to partition a hard drive include:

Assigning the boot system to a different partition than application and data files can help many computers run more smoothly and minimize damage in a system crash.

Storing the swap file on its own partition is sometimes necessary or useful.

Creating a separate partition for the operating system can help it run properly. Some operating systems can't run on a large partition.

Assigning log files to be stored on distinct partitions can help minimize the effects of a system crash caused by excessively large log files.

Assigning distinct operating systems to run on separate partitions allows a multiple boot system setup.

Unallocated space is space on a partition that has not been assigned to a volume. You cannot store or read data in unallocated space.

Volume A volume is a single accessible storage area within a file system. A volume can encompass a single partition or span multiple partitions depending on how it is configured and the operating system you are using. Volumes are identified by drive letters.

Directory A directory (also called a folder) is a container in a volume that holds files or other directories. You use it to logically sort and organize data to keep related files grouped together. Most operating systems use a hierarchal filing structure.

File A file is a one-dimensional stream of bits treated as a logical unit.

Files are the most basic component that a file system uses to organize raw bits of data on the storage device itself.

The file name is made up of the directory path plus the file name.

An extension can also be added to the filename to identify the file type and the program used to create, view, and modify the file.

File systems take many forms. Some common ones (other than exFAT, FAT32, and NTFS) include:

Compact Disk File System (CDFS) - A virtual file system used with Linux.

Network File System (NFS) - A distributed file system that allows client computers to access files over a computer network.

Ext4 - The default Linux file system (and its predecessor ext3, which is still in use).

Formatting

Formatting is the process of preparing a partition to use a specific file system. Be aware of the following facts regarding formatting:

When you format a disk, you identify the file system type and identify the cluster size used to store data.

Reformatting removes the existing file system and replaces it with the new file system type. Reformatting a drive deletes all existing data.

If your system or disk supports multiple operating systems, be sure to select a file system supported by all operating systems you will use.

Microsoft does not recommend the use of NTFS on a volume that is smaller than approximately 400 MB (due to the amount of space overhead involved in NTFS).

When using NTFS on removable devices, you must use the Safely Remove Hardware feature before removing the flash device to prevent file corruption.

A Full format removes the files from the partition. The hard disk is also scanned for bad sectors.

A Quick format removes the reference (or index) to the files, but the files are still there. Because the reference to the files has been deleted, the files are inaccessible. The disk is not scanned for bad sectors.

When configuring A hard drive, you must choose a file system for computer. The following table explains the characteristics of the file systems supported in Windows systems:

Property FAT32 NTFS

Partition size 2 terabytes* 256 terabytes

Volume size 2 terabytes* 256 terabytes

File name length Long File Names (255 characters, spaces) Unicode (255 characters, anything but /)

File size 4 gigabytes 16 terabytes

Number of files allowed 268,435,437 4,294,967,295

Although a FAT32 partition can be up to 2 terabytes, the Windows Disk Management tool can create only a 32 GB FAT32 partition. To create larger FAT32 partitions, you must use the Command Prompt, PowerShell, or a third-party tool.

NTFS

For Windows systems, you will typically choose NTFS over FAT for hard drives to take advantage of additional features not supported by FAT such as:

The ability to format larger partition sizes in Windows.

Smaller cluster sizes for more efficient storage with less wasted space.

File and folder permissions to control access to files.

Encryption to hide the contents of a file.

Compression to reduce the amount of space used by files.

Disk quotas to restrict the amount of disk space that files saved by a user can use.

Volume mount points that allow you to map disk space on another partition into an existing volume.

exFAT

exFAT (sometimes called FAT64) file system is a special file system that is designed to support large flash drives. Using NTFS on flash drives is usually not a good idea due to its high overhead and risk of corruption if the device is not stopped properly prior to removal.

However, many flash drives exceed the 32 GB limit discussed above. Microsoft introduced native exFAT support in Windows 7 to allow large removable flash storage devices to continue to use a FAT-type file system.