HPFS or High Performance File System is a file system created specifically for the OS/2 operating system to improve upon the limitations of the FAT file system. It was written by Gordon Letwin and others at Microsoft and added to OS/2 version 1.2, at that time still a joint undertaking of Microsoft and IBM. For other uses, see Software developer (disambiguation). ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... 1989 is a common year starting on Sunday of the Gregorian calendar. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... In computer engineering, hard disk drive partitioning is the creation of logical divisions upon a hard disk that allows one to apply operating system-specific logical formatting. ... A Master Boot Record (MBR), or partition sector, is the 512-byte boot sector that is the first sector (Sector 0) of a partitioned data storage device such as a hard disk. ... A simple B+ tree example linking the keys 1-7 to data values d1-d7. ... A simple B+ tree example linking the keys 1-7 to data values d1-d7. ... A simple B+ tree example linking the keys 1-7 to data values d1-d7. ... A gibibyte is a unit of information or computer storage. ... A tebibyte is a unit of information or computer storage, commonly abbreviated TiB. 1 tebibyte = 240 bytes = 1,099,511,627,776 bytes The tebibyte is closely related to the terabyte, which can either be a synonym for tebibyte, or refer to 1012 bytes = 1,000,000,000,000 bytes... In computer file systems, a fork is additional data associated with a file system object. ... Most modern file systems have methods of administering permissions or access rights to specific users and groups of users. ... Filesystem-level encryption, is a form of disk encryption where individual files or directories are encrypted by the file system, in contrast to full disk encryption where the entire partition or disk, where the file system resides, is encrypted. ... An operating system (OS) is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. ... Windows NT (New Technology) is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. ... This article is about operating systems that use the Linux kernel. ... FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4. ... For library and office filing systems, see Library classification. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... An operating system (OS) is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. ... File Allocation Table (FAT) is a partially patented file system developed by Microsoft for MS-DOS and was the primary file system for consumer versions of Microsoft Windows up to and including Windows Me. ... Microsoft staff photo from December 7, 1978. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... International Business Machines Corporation (IBM, or colloquially, Big Blue) (NYSE: IBM) (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, New York, USA. The company manufactures and sells computer hardware, software, and services. ...

Among its improvements are:

• support for mixed case file names, in different code pages
• support for long file names (256 characters as opposed to FAT's 11 characters)
• more efficient use of disk space (files are not stored using multiple-sector clusters but on a per-sector basis)
• an internal architecture that keeps related items close to each other on the disk volume
• less fragmentation of data
• extent-based space allocation
• separate datestamps for last modification, last access, and creation (as opposed to FAT's one last modification datestamp)
• a B+ tree structure for directories
• root directory located at the mid-point, rather than beginning of the disk, for faster average access

HPFS also can keep 64 KiB of metadata ("extended attributes") per file. Mixed case is the standard usage of upper-case and lower-case letters. ... In computing, file system fragmentation, sometimes called file system aging, is the inability of a file system to lay out related data sequentially (contiguously), an inherent phenomenon in storage-backed file systems that allow in-place modification of their contents. ... A simple B+ tree example linking the keys 1-7 to data values d1-d7. ... A kibibyte (a contraction of kilo binary byte) is a unit of information or computer storage, commonly abbreviated KiB (never kiB). 1 kibibyte = 210 bytes = 1,024 bytes The kibibyte is closely related to the kilobyte, which can be used either as a synonym for kibibyte or to refer to... Metadata is data about data. ... Extended file attributes is a filesystem feature that enables users to associate arbitrary metadata with computer files, whereas regular attributes have a strictly defined purpose (such as permissions or records of creation and modification times). ...

IBM offers two kind of IFS drivers for this file system: The Installable File System (IFS) is a Filesystem API in IBM OS/2 and Microsoft Windows NT that enables the operating system to recognize and load drivers for filesystems. ...

• the standard one with a cache limited to 2 MiB
• HPFS386 provided with the server versions of OS/2

HPFS386's cache is limited by the available memory and was implemented in assembler. Thus, HPFS386 is faster, but IBM is required to pay Microsoft for each copy sold. It is highly tunable by experienced administrators. See the terminology section, below, regarding inconsistent use of the terms assembly and assembler. ...

IBM had still had right over HPFS , but not HPFS386.

Because of the Microsoft dependence and the long disk check times after a crash, IBM ported the journaling file system JFS to OS/2 as a substitute. A journaling (or journalling) file system is a file system that logs changes to a journal (usually a circular log in a specially-allocated area) before actually writing them to the main file system. ... JFS is a journaling filesystem created by IBM. It is available under an open source license. ...

DOS and Linux support HPFS via third-party drivers. Windows NT versions 3.51 and earlier had native support for HPFS. Windows NT (New Technology) is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. ...

Windows Native Support

Windows 95 and its successors Windows 98, Windows ME could only read/write HPFS when mapped via a network share, but could not read it from a local disk. They listed the NTFS partitions of networked computers as "HPFS", because NTFS and HPFS share the same filesystem identification number in the partition table. Windows 95 is a consumer-oriented graphical user interface-based operating system. ... Windows 98 (codenamed Memphis) is a graphical operating system released on June 25, 1998 by Microsoft and the successor to Windows 95. ... Windows Millennium Edition, or Windows Me (IPA pronunciation: [miː], [ɛm iː]), is a hybrid 16-bit/32-bit graphical operating system released on September 14, 2000 by Microsoft. ... NTFS is the standard file system of Windows NT, including its later versions Windows 2000, Windows XP, Windows Server 2003, Windows Server 2008, and Windows Vista. ...

Windows NT 3.1 and 3.51 had native read/write support for local disks and could even be installed onto an HPFS partition. This was because Microsoft at the time was creating OS/2 version 3 and implemented the filesystem. Windows NT 3. ... Windows NT 3. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

Windows NT 4 still could read and write from local HPFS formatted drives however, using HPFS was discouraged starting with Windows NT 4 and in subsequent versions. Starting with Windows 2000 the filesystem driver pinball.sys enabling the read/write access was removed from the default installation. Pinball.sys was included on the installation media for Windows 2000 and could still be manually installed and used with some limitations.^{[citation needed]} Later Windows versions did not ship with this driver. Windows NT 4. ... Windows 2000 (also referred to as Win2K) is a preemptive, interruptible, graphical and business-oriented operating system designed to work with either uniprocessor or symmetric multi-processor computers. ...

Windows XP Professional allows to read and write like Windows 2000 since they are similar in code.

See also

• Comparison of file systems

The following tables compare general and technical information for a number of file systems. ...

Further reading

• Roy Duncan (September 1989). "Design goals and implementation of the new High Performance File System". Microsoft Systems Journal 4:5: 1–13. 
• Bridges, Dan. "Inside the High Performance File System", Significant Bits magazine, 1996. 
• Chris Graham. Appendix G — HPFS internals. The Graham Utilities for OS/2 - Version 2.
• How to get Windows NT 4, Windows 2000, and Windows XP to read HPFS partitions