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LOADHIGH (LH)

Load the program into the upper memory area. Loading the program into the upper memory area can reserve more conventional memory space for other programs to use (for information on memory optimization, see the "Get More Available Memory" chapter in the "MS-DOS 6.22 User's Manual").

Syntax:

LOADHIGH filename

To specify the memory area where the program is loaded, use the following syntax:

LOADHIGH ...] ]
filename

LOADHIGH can be abbreviated as LH.

Switch options:

/L:region1...]

Specify the memory area where the program is loaded. If /L is not used, MS-DOS will load the program into the largest free upper memory block (UMB) and make other available UMBs available to this program. Using /L can specify the specific memory area where the program is loaded or the memory area that the program can use.

Specify the area number after the /L switch to load the program into the largest free memory block in the specified area. For example, to load the program into the largest free memory block in area 4, enter /L:4 (enter the MEM /F command line to list free memory areas).

When using the /L switch, the program can only use the specified memory area. For a program that needs to use multiple memory areas, multiple areas can be specified (use the MEM /M command and give the program name as a parameter to view the memory usage of the program). When specifying multiple areas, separate the memory block numbers with a semicolon (;). For example, to use memory blocks 2 and 3, enter /L:2 ; 3.

Usually, MS-DOS loads the program into the specified memory area containing the UMB that exceeds the program loading size (the program loading size is usually equal to the size of the executable file). If the space required by the program during operation is larger than the loading size, the minsize parameter can be used to ensure that the program is not loaded into a UMB smaller than the space required for operation. MS-DOS will load the program into a UMB larger than the program loading size and the size specified by minsize.

/S
Shrink the UMB to the minimum size when loading the program. Using this switch can use memory most efficiently. This switch is usually only used by the MemMaker program. MemMaker can analyze the memory usage of the program to determine whether it is safe to use this switch when loading the program. This switch can only be used with the /L switch and only affects UMBs that specify a minimum size.

Parameters:

filename
Specify the location and name of the program to be loaded.

parameters
Specify the command-line parameters required by the program.

Related commands:

For information on loading device drivers into the upper memory, see the <DEVICEHIGH> command.

For information on using MemMaker to move programs to the upper memory area, see the <MEMMAKER> command.

LOADHIGH (LH)─Notes

Requirement: DOS=UMB command

Before using the LOADHIGH command, you must add the DOS=UMB command in the CONFIG.SYS file. For more information on the DOS=UMB command, see the <DOS> command.

Automatically optimizing the upper memory area using MemMaker

The MemMaker program included in MS-DOS 6.22 can automatically optimize the use of system memory. MemMaker scans the upper memory, analyzes the memory usage of drivers and applications to determine the programs most suitable for loading into available UMBs. MemMaker adds the LOADHIGH command to the AUTOEXEC.BAT file and specifies /L and /S switches when needed. For more information on MemMaker, see the "Get More Available Memory" chapter in the "MS-DOS 6.22 User's Manual".

Must install an upper memory manager

Before being able to load programs into the upper memory area, an upper memory manager must be installed. MS-DOS provides EMM386.EXE for 80386 or higher computers to manage upper memory. You can install EMM386 using the DEVICE command in the CONFIG.SYS file (the DEVICE command for installing the HIMEM.SYS extended memory manager must come before the DEVICE command for installing EMM386)

How LOADHIGH works

When using LOADHIGH to load a program, MS-DOS will try to load the program into the upper memory area. If the upper memory area is not enough, MS-DOS will load the program into conventional memory. Use the MEM /M command and specify the program name to find out whether the program uses UMB.

Using LOADHIGH in AUTOEXEC.BAT

The most convenient way to use the LOADHIGH command is to use the LOADHIGH command in AUTOEXEC.BAT. (If the MemMaker program is used, the program will automatically add the required LOADHIGH command to the AUTOEXEC.BAT file.)

LOADHIGH (LH)─Examples

The following command line loads the DOSKEY program into the upper memory area and specifies that MS-DOS loads the program into memory area 1:

loadhigh /l:1 c:\dos\doskey

The following command line loads the MYPROG.EXE program into memory area 1 and allows the program to use upper memory areas 3 and 4:

lh /L:1;3;4 c:\programs\myprog.exe

The following command line loads the MYPROG program into conventional memory (area 0) and allows the program to access upper memory area 1:

loadhigh /l:0;1 c:\programs\myprog.exe