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Dos

  • 项目

Specifies that the MS-DOS subsystem is to maintain a link to the upper memory area (UMA) or is to load part of itself into the high memory area (HMA).

Syntax

dos={high|low}[{,umb|,noumb}]

dos={[high,|low,}]{umb|noumb}

Parameters

{ high | low } : Specifies whether the MS-DOS subsystem should attempt to load a part of itself into the HMA. Use high to enable the MS-DOS subsystem to load itself into the HMA. Use low to keep all of the MS-DOS subsystem in conventional memory. The default setting is low.

{ umb | noumb } : Specifies whether the MS-DOS subsystem should maintain a link between conventional memory and the UMA. Umb provides this link. Noumb disconnects this link. The default setting is noumb.

/?   : Displays help at the command prompt.

Remarks

  • Installing Himem.sys for dos=umb or dos=high 

    You must install the Himem.sys device driver before you specify either dos=umb or dos=high.

  • Using umb 

    You must specify dos=umb to load programs and device drivers into the upper memory area (UMA). By using UMA, you free more space in conventional memory for programs. In addition, you must install an upper memory block (UMB) provider.

  • Using the high parameter

    If you specify the high parameter, the MS-DOS subsystem attempts to load part of itself into the high memory area (HMA). Loading part of MS-DOS into the HMA frees conventional memory for programs.

  • Combining parameters

    If you specify the high parameter, the MS-DOS subsystem attempts to load part of itself into the high memory area (HMA). By loading part of MS-DOS into HMA, you free conventional memory for programs.

    You can include more than one parameter on a single dos command line, using commas to separate them. For example, the following syntax is valid:

    dos=umb,low
    dos=high,umb

    You can place the dos command anywhere in your Config.nt or equivalent startup file.

Formatting legend

Format

Meaning

Italic

Information that the user must supply

Bold

Elements that the user must type exactly as shown

Ellipsis (...)

Parameter that can be repeated several times in a command line

Between brackets ([])

Optional items

Between braces ({}); choices separated by pipe (|). Example: {even|odd}

Set of choices from which the user must choose only one

Courier font

Code or program output

Devicehigh

Loadhigh

Command-line reference A-Z