32-bit File Access

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Categories: Microsoft Windows file system technology | Windows disk file systems | Microsoft Windows stubs

32-bit file access refers to the higher performance, protected mode disk caching method introduced in Windows for Workgroups 3.11, which replaced SmartDrive (Smartdrv).

32-bit file access bypassed MS-DOS and directly accessed the disk, either via the BIOS or (preferably) 32-bit disk access (Windows-native protected mode disk drivers). This feature was a backport from the then-unreleased Windows 95, as suggested by Microsoft's advertisements for Windows for Workgroups 3.11 ("the 32-bit file system from our Chicago project").

32-bit file access and the introduction of Long File Names in Windows 95 reduced DOS to the role of a boot loader for Windows.

32-bit file access was implemented using the VFAT, VCACHE, and IFSMgr VxD drivers.

32-bit file access should not be confused with 32-bit disk access. Although both technologies are similar, 32-bit disk access (also known as FastDisk) pre-dates Windows for Workgroups 3.11. 32-bit file access provided a 32-bit code path for Windows to directly access the disk bus by intercepting the MS-DOS Int 21H services while remaining in 386 protected mode and at CPU speeds, rather than handling the Int 21H services in real mode by MS-DOS. 32-bit disk access relatively offers less performance and is less likely to work on many computers than 32-bit file access. 32-bit file access does not need 32-bit disk access.