A file system is the method by which an OS stores, organizes files and manages access to files on a storage device, such as a hard drive. File systems differ in how they allocate space for files, how files are located on a disk, what level of fault tolerance is built into the system, and how access to files is secured. Regardless of how these tasks are accomplished, contemporary file systems have the following objectives:
Provide a convenient interface for users and applications to open and save files.
Provide an efficient method to organize space on a drive.
Provide a hierarchical filing method to store files.
Provide an indexing system for fast retrieval of files.
Provide secure access to files for authorized users.
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When a user double-clicks a file to open it, the user interface calls the file system with a request to open the file. The file type determines exactly how the file is opened. If the file is an application, the application is loaded into memory and run by the CPU. If the file is a document, the application associated with the document type is loaded into memory and opened by the application. For example, if you double-click the Budget.xls file, the Excel application is loaded into memory and then opens the Budget.xls document file. If a user creates a new file or changes an existing file and wants to save it, the application calls the file system to store the new or changed file on the disk. Most users of an OS interact with the file system by using Windows Explorer or a similar file manager program on another OS, but as a future computer or network professional, you need to have a deeper understanding of how a file system works so that you can make informed choices when you need to install a file system or troubleshoot file system-related problems.
There are two types of file systems used on Windows operating systems today.
- FAT32(File Allocation Table
- NTFS (New Technology File System).
FAT32 is the older of the two file formats. FAT32 is the most common version of the FAT (File Allocation Table) file system created back in 1977 by Microsoft. It eventually found its way on the IBM PC's PC-DOS in 1981 and carried over to MS-DOS when that became a standalone product. FAT had been the standard format for floppy disks and hard drives all through the DOS years, and versions of Windows up to and including Windows 8. FAT-16 or FAT-32 was used on these systems MS-DOS and Windows 95/98/NT/2000/XP
NTFS (New Technology Files System) is the newer drive format. Microsoft introduced NTFS in 1993, as a component of the corporate-oriented Windows NT 3.1 and then Windows 2000, though it didn't become common on consumer PCs until Windows XP in 2001. Windows 7 and 8 default to NTFS format on new PCs.
Compatibility
FAT32 is read/write compatible with a majority of recent and recently obsolete operating systems, including DOS, most flavors of Windows (up to and including 8), Mac OS X, and many flavors of UNIX-descended operating systems, including Linux and FreeBSD.
NTFS, on the other hand, is fully read/write compatible with Windows from Windows NT 3.1 and Windows XP up to and including Windows 8. Mac OS X 10.3 and beyond have NFTS read capabilities, but writing to NTFS volume requires a third party software utility like Paragon NTFS for Mac. There are other hacks and workarounds for NTFS on the Mac, but in any case NTFS is only semi-compatible with OS X. NTFS on Linux systems is spotty for both read and write operations. Look for NTFS-3G driver support on your Linux support page to see if it's built in.
File Size Matters
FAT32 file size support tops out at 4GB and volume size tops out at 2TB. This means that you're limited to 2TB FAT32 partitions if you want to use a 4TB drive. It also means that you are limited to 4GB files. This is a concern with uncompressed high-definition movie files, where 30GB files are not unheard of. Theoretically, NTFS is limited by design to 16EB (Exabytes). One Exabyte is the equivalent of one billion Gigabytes, so we're quite a ways away from maxing out NTFS. In practice, 2 to 4TB volumes are the limit at this time. Larger volumes will require a 64-bit OS and compatible hardware.
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