Editing Installable File System (section)

===IFS in Windows NT===
The IFS API is part of the [[Windows Driver Kit]].

When Microsoft stopped developing OS/2 and concentrated on what was then called OS/2 NT, they took the IFS ideas with it, along with the HPFS filesystem.

Instead of being a four-piece scheme, NT IFS was redesigned into a two-piece scheme.
microIFS and miniIFS were removed from the scheme. IFS and helpers remain as the same, but later, in Windows NT 4.0, a [[defragmentation]] helper (DEFRAG) was added.
Microsoft's original NTLDR was coded for loading the NT kernel from FAT, [[High Performance File System|HPFS]] or [[NTFS]], but subsequent versions dropped HPFS support.  All of the drivers and helpers became 32-bit [[Portable Executable|PE executables]]. The FAT file system was moved out of the Kernel to an IFS and was heavily optimized for performance, taking advantage of the 32-bit processing capabilities (being called [[FASTFAT]]).

Original Windows NT 3.1 incorporated FAT, HPFS (Pinball) and the newly created NTFS drivers, along with a new and improved CD-ROM filesystem driver that incorporated long file names using the [[Joliet (file system)|Microsoft Joliet]] filesystem.

Windows NT 3.51 added per-file compression to NTFS and to the IFS interface.
In Windows NT 4.0 HPFS was removed. In Windows 2000 FASTFAT was updated to support FAT32 and [[Universal Disk Format|UDF]] was added.

Windows 2000 modified the IFS interface to add per-file encryption.

Network file-sharing protocols and antivirus are also implemented using IFS 'file system filter' drivers which intercept file I/O operations.<ref>{{cite web | url=https://docs.microsoft.com/en-us/windows-hardware/drivers/ifs/about-file-system-filter-drivers | title=About file system filter drivers - Windows drivers | date=15 December 2021 }}</ref>

[[Apple Inc.|Apple]] started including read only [[HFS+]] drivers in [[Mac OS X 10.6]]'s version of [[Boot Camp (software)|Boot Camp]]<ref>{{cite web|title=Snow Leopard's Boot Camp Includes HFS + Windows Drivers|date=6 May 2009 |url=http://www.macrumors.com/2009/05/06/snow-leopards-boot-camp-includes-hfs-windows-drivers/|access-date=14 September 2012}}</ref> for use in [[Windows XP]], [[Windows Vista]], and [[Windows 7]].