HIGH | LOW Determines whether the command environment attempts to load part of itself
into the High Memory Area (HMA) (HIGH) or keep all of the code in conventional memory
(LOW). The default setting is LOW. Generally, you want to load the command environment into
high memory to preserve more conventional memory for applications.
UMB | NOUMB Determines whether the command environment should manage the Upper
Memory Blocks (UMBs) created by a UMB provider. Windows provides a UMB provider as a
default. DOS users used to rely on a special program named EMM386.EXE to perform this task.
The UMB argument tells the command environment to manage the UMBs, which frees additional
memory for loading applications in areas other than conventional memory. The default
setting is NOUMB.
STARTING THE COMMAND INTERPRETER 107
Running DOS Applications Only
You can execute any kind of application you want from the command prompt. If you want to start
Notepad, simply type Notepad and press Enter. However, mixing Windows and older DOS applications
can sometimes cause problems. Developers wrote DOS applications with the expectation
that these applications controlled the entire machine, which can cause myriad problems with
Windows applications.
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