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EMM386.EXE--Notes

Sharing XMS and EMS memory EMM386 provides EMS/VCPI memory for programs that require it by converting XMS memory to EMS/VCPI memory. When it is loaded, EMM386 reserves the amount of memory specified by the MIN switch for use as EMS/VCPI memory (the default value is 256K). Once this amount of XMS memory is reserved, it is always available as EMS/VCPI memory and no longer available as XMS memory. EMM386 may be able to convert additional amounts of XMS memory to EMS/VCPI memory, up to the amount specified by the MEMORY parameter. EMM386 returns the additional amount back to XMS memory when it is no longer needed as EMS/VCPI memory. If you specify MIN=0, EMM386 does not reserve any XMS memory for use as EMS/VCPI memory. Instead, it converts XMS memory to EMS/VCPI memory only when a program requests it. This frees XMS memory when EMS/VCPI memory is not needed. However, EMM386 will not be able to supply the requested amount of EMS/VCPI memory if programs have allocated all the XMS memory at the time of the request. Must install HIMEM.SYS before EMM386.EXE You must include a DEVICE command for the HIMEM.SYS device driver in your CONFIG.SYS file before the DEVICE command for EMM386.EXE. Using EMM386 memory switches Unless you want to use EMM386 to provide access to the upper memory area, you need not specify memory switches on the DEVICE command line. EMM386 usually runs properly with the default values. In some cases, however, you might want to control how EMM386 uses memory. For example, you can control where EMM386 puts the EMS page frame or which segments it uses for EMS pages. You can use as many of these memory switches as you want, in any order you want. CAUTION: Use EMM386.EXE parameters carefully. You can make your computer inoperable if you use them incorrectly. Using EMM386 to provide access to the upper memory area In addition to providing access to expanded memory, EMM386 provides access to the upper memory area, which you can use to load certain programs and device drivers. You must use either the RAM or NOEMS switch to provide access to the upper memory area. To give MS-DOS access to the upper memory area but not to expanded memory, use the NOEMS switch. To give MS-DOS access to both the upper memory area and expanded memory, use the RAM switch. The RAM switch provides access to less of the upper memory area for running device drivers and programs than does the NOEMS switch. In either case, you must include the DOS=UMB command in your CONFIG.SYS file. The device command for EMM386.EXE must precede any DEVICEHIGH commands. Using EMM386 with Windows 3.1 When EMM386 is used with Windows 3.1, the I, X, NOEMS, Mx, Pnnnn, and FRAME switches have precedence over the EMMINCLUDE, EMMEXCLUDE, and EMMPAGEFRAME settings in the Windows SYSTEM.INI file. Changes to these settings in the SYSTEM.INI file have no effect when EMM386 is loaded. SMARTDRV double buffering may be required to use EMM386 If you have a small computer system interface (SCSI) or enhanced system device interface (ESDI) hard disk or other device, you may have to add the following line to your CONFIG.SYS file: device=smartdrv.exe /double_buffer Add the line before any DEVICEHIGH statements and before any statements that load installable device drivers that use expanded memory. The statement enables an SCSI or EDSI controller to transfer information to programs that use the upper memory area or expanded memory.
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