2 GB limit

The 2 GB limit refers to a physical memory barrier for a process running on a 32-bit operating system, which can only use a maximum of 2 GB of memory.^[1] The problem mainly affects 32-bit versions of operating systems like Microsoft Windows and Linux, although some variants of the latter can overcome this barrier.^{[citation needed]} It is also found in servers like FTP servers or embedded systems like Xbox.^{[citation needed]} The use of Physical Address Extension (PAE) can help overcome this barrier.^{[clarification needed]}

While Linux, FreeBSD, and most Unix-like operating systems support PAE so long as the hardware does,^[2]^[3] Windows needs this boot option enabled manually. This is known as 4-gigabyte tuning (4GT), or the /3GB switch. Once enabled, executables can have the "large address aware" flag set to increase their memory limit to 3 GB. 32-bit processes on 64-bit Windows are also limited to 2 GB. However, they can use the "large address aware" flag as well, except that it doesn't require the /3GB switch and increases the limit to 4 GB.^[4]

It could also refer to the maximum partition size for the FAT16 file system in versions of Windows prior to XP.^[5]

References

^ Richardson, Mike (2014-07-24). "Overcoming the Windows 2GB Caching Limit". O'Reilly Media. Archived from the original on 2015-09-13. Retrieved 2015-08-18.
^ "2.3.23-pre4 x86 64 GB RAM changes [HIGHMEM patch] explained a bit". 1999-10-10. Retrieved 2017-09-17.
^ "Chapter 4. Hardware Compatibility". Retrieved 2017-09-17.
^ "Memory Limits for Windows and Windows Server Releases". Microsoft. Retrieved 2017-09-17.
^ "Maximum partition size using the FAT16 file system in Windows XP". Microsoft. Retrieved 2015-08-18.

References

See also