32-bit Disk Access

From Wikipedia, the free encyclopedia

32-bit Disk Access refers to a special disk-caching and writing mode available in 32-bit operating systems, that may or may not run purely 32-bit applications. Sometimes enabling this mode on older operating systems would break older applications of the day.

Contents 1 Windows 3.1 2 Windows 9x 3 Other Operating Systems 4 References

[edit] Windows 3.1

Windows 3.1 had an option in its 386 Enhanced control panel that would enable 32-bit read & write access in 386 enhanced mode. Usually, 32-bit read could be safely enabled, but 32-bit write had issues with a number of applications. 32-bit Disk Access was the feature that made it possible to page MS-DOS applications to disk. Without it, if the Int 13h handler was paged out, the virtual machine would loop forever.

[edit] Windows 9x

Windows 95, Windows 98, and Windows Me use protected mode disk drivers that are 32-bit in nature.

Safe Mode uses real mode disk drivers that disable native OS 32-bit disk access.

[edit] Other Operating Systems

Windows NT, and therefore Windows 2000, Windows XP and later always have 32-bit disk drivers active.

See also: 32-bit File Access

[edit] References

• Explanation of SMARTDRV & 32-bit disk access from Microsoft
• 32-bit in Windows 3.1 / 9x
• Windows driver support for large hard drives