HIMEM.SYS
| Microsoft Windows 的组件 | |
 | |
| 其他名称 | HIMEM (often simply referred as such) |
|---|---|
| 类型 | Device driver |
| 推出于 | Windows/386 2.1 MS-DOS 5 IBM DOS 5 |
| 包含于 | MS-DOS IBM PC-DOS Windows 3.0 Windows 3.1x Windows 9x |
| 最后包含于 | Windows Me |
HIMEM.SYS (often simply referred to as HIMEM) is a device driver file for MS-DOS and other DOS systems that enables them to use extended memory (i.e. memory above the 1MB conventional memory barrier) on 80286 machines and above. It implements the Extended Memory Specification, providing control over the A20 line, access to both the High Memory Area (the 65520 bytes immediately following the 1MB line, starting at FFFF:0010) and the rest of extended memory, allocating it and copying between extended and conventional memory. If loaded in CONFIG.SYS, it can be used to load DOS into the HMA, freeing up conventional memory.
It is required by Windows/386 2.1x and Windows 3.x to run in 386 Enhanced Mode. An EXE version of the driver is included on the Windows 9x distribution media that can load after DOS startup if no XMS driver is available, XMSMMGR.EXE.