DEVICEHIGH--Notes

Using the DOS=UMB command

To use the DEVICEHIGH command, you must also include the DOS=UMB command in
your CONFIG.SYS file. If you do not specify this command, all device drivers
are loaded into conventional memory, as if you had used the DEVICE command.
For more information, see the <DOS> command.

Using MemMaker to optimize upper memory area automatically

The MemMaker program, included with MS-DOS, automatically optimizes your
system's memory. MemMaker surveys the upper memory area, analyzes the memory
use of your drivers and programs, and determines which drivers and programs
fit best into the available UMBs. MemMaker then changes selected DEVICE
commands in your CONFIG.SYS file to DEVICEHIGH commands and adds /L and /S
switches as necessary. For more information about using MemMaker to optimize
your computer's memory, see "Making More Memory Available" in the MS-DOS
User's Guide.

Using MS-DOS 5 DEVICEHIGH syntax

The version of DEVICEHIGH provided with MS-DOS 5 used the following syntax:

    DEVICEHIGH SIZE=hexsize [drive:][path] filename [dd-parameters]

Although the MS-DOS 5 DEVICEHIGH syntax will still work with MS-DOS 6.22, it
is strongly recommended that you use the current DEVICEHIGH syntax whenever
possible.

Installing HIMEM.SYS and a UMB provider

To load a device driver into the upper memory area, your computer must have
extended memory. You must use the DEVICE command once to install the
HIMEM.SYS device driver and then again to install an upper-memory-block
(UMB) provider. These commands must appear before the DEVICEHIGH command in
your CONFIG.SYS file. If your computer has an 80386 or 80486 processor, you
can use EMM386.EXE as the UMB provider. If your computer has a different
processor, you must supply a different UMB provider.

If no upper memory area is available

If there is not enough upper memory area available to load the device driver
you specified with the DEVICEHIGH command, MS-DOS will load it into
conventional memory (as if you had used the DEVICE command).