Search results
Results from the WOW.Com Content Network
Extended memory is located above 1 MB, includes the high memory area, and ends at 16 MB on the Intel 286 and at 4 GB on the Intel 386DX and later. In DOS memory management, extended memory refers to memory above the first megabyte (2 20 bytes) of address space in an IBM PC or compatible with an 80286 or later processor.
Mac OS X Tiger through Mac OS X Snow Leopard support PAE and the NX bit on IA-32 processors; Snow Leopard was the last version to support IA-32 processors. On x86-64 processors, all versions of macOS use 4-level paging (IA-32e paging rather than PAE) to address memory above 4GB. Mac Pro and Xserve systems can use up to 64 GB of RAM. [23]
The 1 MB total address space was a result of the 20-bit address space limit imposed on the 8088 CPU. Using the color video buffer space, some third-party utilities could add memory at the top of the 640k conventional memory area, to extend memory up to the base address used by hardware adapters. This could ultimately backfill RAM up to the MDA ...
Certain emulation programs, colloquially known as LIMulators, did not rely on motherboard or 80386 features at all. Instead, they reserved 64 KiB of the base RAM for the expanded memory window, where they copied data to and from either extended memory or the hard disk when application programs requested page switches.
The application had to keep track of which bank of expanded memory contained a particular piece of data, and when access to that data was required, the application had to request (through a driver program) the expanded memory board to map that part of memory into the processor's address space. Although applications could use expanded memory ...
However, even with video RAM, the ROM BIOS, the Video BIOS, the Option ROMs, and I/O ports for peripherals, much of this 384 KB of address space was unused. As the 640 KB memory restriction became ever more of an obstacle, techniques were found to fill the empty areas with RAM. These areas were referred to as upper memory blocks (UMBs).
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
BTX (for Balanced Technology eXtended) is a form factor for motherboards, originally intended to be the replacement for the aging ATX motherboard form factor in late 2004 and early 2005. It was designed to alleviate some of the issues that arose from using newer technologies (which often demand more power and create more heat) on motherboards ...